IAN ALEXANDER EWING AND MARGARET ANN EWING AGAINST INVERCLYDE COUNCIL
SHERIFFDOM OF NORTH STRATHCLYE AT GREENOCK
[2016] SC GRE 65
B434/14
JUDGMENT OF SHERIFF DEREK J HAMILTON
In the cause
IAN ALEXANDER EWING and MARGARET ANN EWING, residing together in Larbert
Pursuers
Against
INVERCLYDE COUNCIL, a local authority and in terms of the Local Government (Scotland) Act 1994, having its principal office at Municipal Building, Clyde Square, Greenock, PA15 1LY
Defender
Pursuers: Mr Douglas Fairley QC, instructed by Mr K Carruthers, Solicitor, Morton Fraser, Solicitors, Edinburgh
Defender: Mr Mark Lindsay QC, instructed by Mr J Douglas, Solicitor, Inverclyde Council
GREENOCK: 18 August 2016
The sheriff, having resumed consideration of the cause:-
Finds the following facts admitted or proved;
Parties
1 The Pursuers Ian Ewing and Margaret Ewing, reside in Larbert. They are the owners of property at Flat 3/3, 19 Robert Street, Port Glasgow, the subjects of this appeal. They are also the Pursuers in case reference B435/14 (Flat 3/1, 19 Robert Street, Port Glasgow).
2 Priya Properties Limited, is a company incorporated under the Companies Acts having its registered office at 1 Mansion Avenue, Port Glasgow PA14 6QP. It is the Pursuer in actions B462/14 (Flat 3/2, 8 Bruce Street, Port Glasgow) and B463/14 (Flat 3/1, 8 Bruce Street, Port Glasgow).
3 Port Glasgow Training Initiative, is a company incorporated under the Companies Acts having its registered office at Millburn, Newark Place, Port Glasgow, PA14 5PL It is the Pursuer in actions B502/14 (Flat 3/2, 23 Robert Street, Port Glasgow) and B512/14 (Flat 3/2, 8 Clune Park Street, Port Glasgow).
4 The Defender is the local authority for Inverclyde.
Demolition Orders
5 Mr. John Arthur was the Head of Safer and Inclusive Communities for the Defender.
6 Between September 2013 and 14th March 2014, Mr Arthur received and considered a report by David Turnbull of ATK Partnership, Greenock, dated 11th March 2014, Production 9.
7 On or about 5th June 2014, Mr Arthur received and considered a report by Stanger Testing Services Limited, dated 5th June 2014, Production 11.
8 Having considered the terms of the ATK report, and the statutory guidance issued by the Scottish Government in March 2009 titled: “Implementing the Housing (Scotland) Act 2006, Parts 1 and 2: Advisory and Statutory Guidance for Local Authorities: Volume 4 – Tolerable Standard”, on 11 March 2014 and 6 May 2014, Mr Arthur recommended to the Defender that it should make demolition orders under Section 115 of the Housing (Scotland) Act 1987 in respect of all properties forming the Clune Park estate, including the properties which are the subject of these appeals.
9 The Defender accepted Mr Arthur’s recommendation, and on 26th June 2014, under Section 115 of the Housing (Scotland) Act made inter alia the demolition orders referred to herein.
10 On 26 June 2014, the Defender served demolition orders and accompanying letters on the Pursuers Ian and Margaret Ewing, in respect of the properties at Flats 3/1 and 3/3, 19 Robert Street, Port Glasgow.
11 On 26 June 2014, the Defender served demolition orders and accompanying letters on Priya Properties Limited, in respect of the properties at Flats 3/1 and 3/2, 8 Bruce Street, Port Glasgow.
12 On 26 June 2014, in respect of the properties at Flat 3/2, 23 Robert Street and Flat 3/2 Clune Park Street, Port Glasgow, the Defender served demolition orders and accompanying letters on the then owners of the properties, Inverclyde Funeral Services Limited, a company incorporated under the Companies Acts and having its registered office at 1 Lower Bouvirie Street, Port Glasgow PA14 5PE. On or about 29th March 2016, Inverclyde Funeral Services transferred its interests in the properties to Port Glasgow Training Initiative, a company incorporated under the Companies Acts and having its registered office at Millburn, Newark Place, Port Glasgow PA14 5PL.
Clune Park Estate
13 Clune Park estate was built in the early 1900s to provide accommodation for shipyard workers. The influx of skilled workers into the Port Glasgow area had led to an acute shortage of housing. To address that shortage, Clune Park estate was constructed. The estate consists of five “U” shaped four storey tenement buildings comprising, in total, approximately four hundred and thirty individual flats within forty six tenement blocks on six streets, including Robert Street, Maxwell Street, Clune Park Street, Wallace Street, Bruce Street and Caledonia Street. It is sometimes referred to as the Robert Street area or the Clune Park estate.
14 In the late 1970s, the flats on the estate were sold to private sector landlords and owner occupiers.
15 The tenement buildings are of concrete filler-joisted flat roof construction, supported by load-bearing internal and external walls. The front elevations of the tenement buildings have been faced with natural red sandstone which generally has a rock-faced finish to the ground floor, with polished ashlars above. The rear and gable walls are of brickwork finished in roughcast render, and the main internal load-bearing walls are of plastered brickwork. Internal floors of the buildings are of suspended timber construction. The entrance closes, stairs and landings are of concrete.
16 8 Clune Park Street and 8 Bruce Street are both end-terraced tenement blocks.
17 As is common in buildings of this age and form of construction, the elevations contain no movement control joints.
Mechanisms
18 Corrosion Swelling/Expansion
(i) When steel is exposed to moisture, the steel will corrode. When steel corrodes, it can expand to between four and six times its size. As it expands it exerts a force on anything surrounding it. Steel embedded in concrete, therefore, as it corrodes and expands, applies a lateral force which can push the concrete outwards. Corrosion expansion can lead to steel losing its profile or section.
(ii) Evidence of corrosion expansion within concrete roofs, and resultant concrete movement, can sometimes be seen in properties, internally and externally.
(iii) Internally, there might be evidence of rust staining and/or linear cracking on the underside surface of the roof, running along the line of the embedded corroding steel. There might also be spalling plasterwork on the ceiling under the steel, as the steel expands.
(iv) Externally, there might be evidence of cracking between the internal face of the front and rear elevations, and the internal dividing walls, as the elevations are pushed away from the internal walls by the expansion forces. There may also be evidence of external cracking of the gables as the roof spreads across the wall heads due to the expansion forces, and pushes the elevations outwards.
19 Spalling
(i) Spalling is where material is pushed off a surface. Where reinforcement steel bars embedded in concrete corrode and expand, the expansion forces push on the surrounding material. This can cause cracking in the surrounding material. If the surrounding material is still present and remains attached, it might be possible for it to be pushed back into place. Spalling occurs when the surrounding material becomes detached.
20 Carbonation
(i) The cement in concrete provides alkaline conditions. The passive alkalinity of the concrete protects embedded steel. Steel embedded in concrete relies on the concrete to protect it from dampness and corrosion. The depth of cover of the concrete to the steel determines the level of protection for the steel. Carbonation is a natural process where CO2 is absorbed from the air. If the depth of carbonation is to the depth of the reinforcement, the protection to the reinforcement is reduced and the steel is more susceptible to corrosion. In modern construction, a degree of anti-carbonation is applied to steel.
(ii) Carbonation itself does not cause corrosion to steel – it simply reduces the protection that concrete provides in preventing corrosion. Even if concrete is fully carbonated, that is not evidence of corrosion, but simply evidence that the level of protection to the steel has been reduced. Significant corrosion might not occur with carbonated concrete if it is kept indoors in dry conditions, but the corrosion risk will be significantly increased if carbonated concrete is exposed to wet conditions, either indoors or outdoors.
21 Debonding
Debonding is a process where the bond between the concrete and the embedded steel has been lost. The effect is that there is no longer a composite steel and concrete structure, and that has the result of the concrete slab containing an element of dead weight of steel.
22 Deflection
Deflection indicates a change in level. Deflection of a roof might indicate that the roof has dropped in height at a particular point or points. This might be evidenced by ponding of standing water, or by tearing of the flat roof covering where it meets any upstands.
Inspections and findings
23 Mr William Morrison is a fellow of the Royal Institution of Chartered Surveyors; a member of the Chartered Institute of Arbitrators; a member of the Institution of Construction Safety; and an Associate of the Institute of Business Consulting. He is a Divisional Director of Capita Property and Infrastructure, Glasgow. Mr Morrison carried out a visual non-disruptive examination of the six appeal properties on 19th and 21st January 2015. He did not examine any other properties in the Clune Park estate. He inspected and photographed the roofs of the buildings. Mr Morrison prepared two reports dated 13th February 2015 and 19th June 2015, Productions 1 and 2. The second report dealt with the Defender’s rebuttal of his original report, and also commented on the verticality analysis that formed part of the ATK Partnership report. Mr Morrison also attended a joint meeting of experts on 28th July 2015, with a view to preparing a Scott Schedule where defects were identified by the parties, and an effort was made to reach agreement as to the cause of each defect.
24 Mr Iain Balfour is a Chartered Engineer and a director of Balfour Engineering Consultancy Limited, Paisley. He has worked as a structural engineer for twenty four years, and has been a Member of the Institute of Structural Engineers since 1998. Mr Balfour carried out an initial non-disruptive visual inspection on 26th March 2014 and 8th April 2014, and a disruptive survey of seven top floor flats on 29th May 2014. Only two of the flats that were subject to disruptive surveys are appeal properties, (B434/14 Flat 3/3 19 Robert Street, Port Glasgow, and B463/14 Flat 3/1 8 Bruce Street, Port Glasgow). Mr Balfour produced a report dated 13th June 2014, Production 3. On 28th July 2015, Mr Balfour attended the joint site inspection of experts for the preparation of a Scott Schedule.
25 Mr William Johnston is a Civil Engineer with Stanger Testing Services Limited. On 5th June 2014, Stanger Testing Services tested five properties within the Clune Park estate. His inspections included inspections of the roofs. The purpose of the investigation was to carry out a survey of the roof slab construction to determine the steel reinforcement depth of cover, size and spacing, depth of carbonation, and to determine if the roof structure was an in situ concrete slab or precast concrete units. Dust drillings were also to be obtained for chloride content analysis. None of the properties tested were appeal properties, although Flat 3/1 8 Clune Park Street was within the same building as the appeal property, Flat 3/2 8 Clune Park Street (Ref B512/14). Stanger Testing Services produced a report dated 5 June 2014.
26 All the properties inspected by Stanger Testing Services Limited had the same roof structure. The concrete roof slabs had embedded reinforcement steel ribs measuring 7mm by 75 mm, and spaced 600mm apart. There was secondary steel within the concrete slab. The pattern and thickness of the secondary steel was not determined.
27 Mr Paul Hunter is a land surveyor and survey manager with Phoenix Surveys (Scotland) Limited. He carried out verticality surveys of all the buildings within which the appeal properties are located. His remit was to measure the verticality of the buildings on a particular day and to report his findings. He was not instructed to monitor the buildings for any movement. He produced a report dated 23rd March 2015.
28 Mr David Turnbull is a Civil and Structural Engineer and is a Consulting Engineer with the firm of ATK Partnership, Greenock. Mr Turnbull prepared an initial report, dated 14th March 2014, and a supplementary report dated April 2015. On 28th July 2015 he attended the joint site inspection of experts for the preparation of the Scott Schedule.
29 By the time Mr Turnbull had prepared his two reports he had not been inside any of the appeal properties. He had not been on any of the roofs and had relied on photographs provided by the Defender.
30 A joint inspection of the appeal properties was carried out on 28th July 2015. Those present at the inspection included Mr William Morrison and Mr David Turnbull. The following was found as at 28th July 2015;;
(i) Number 19 Robert Street, Flats 3/1 and 3/3
Flat 3/1, 19 Robert Street -
a) there was no internal evidence of rust staining on the ceilings / soffits of the concrete roof slab; and
b) there was no internal evidence of spalling of the ceiling finishes / concrete cover to the embedded reinforcement
Flat 3/3, 19 Robert Street -
a) there was no internal evidence of rust staining on the ceilings / soffits of the concrete roof slab; and
b) there was no internal evidence of spalling of the ceiling finishes / concrete cover to the embedded reinforcement.
South (Front) Elevation of the building -
a) the pointing to the stone ashlars of the elevation and the chimney head at roof level was cracked and open; and
b) there were cracks at the window openings and Rybat stones to one of the windows at the second floor and to one of the windows at the third floor.
North (Rear) Elevation of the building -
a) there was evidence of horizontal cracking at the head of the top floor window openings; and
b) there was evidence of diagonal stepped cracking at the steps in roof slabs between adjacent properties or closes.
(ii) Number 23 Robert Street, Flat 3/2
Flat 3/2, 23 Robert Street -
a) there was no internal evidence of rust staining on the ceilings / soffits of the concrete roof slab; and
b) there was no internal evidence of spalling of the ceiling finishes / concrete cover to the embedded reinforcement.
South (Front) Elevation of the building -
a) there was evidence of cracks at the head of the third floor window openings where the roof slab projected beyond the chimney head. The cracks were not the result of settlement or ground conditions;
b) there was evidence of vertical stepped cracks at the window openings to the west of the close door entrance at the third floor level;
c) there was evidence of horizontal “shake” in ashlar level with the third floor level. This was caused by a natural defect or weakness in the bedding plane of the sedimentary sandstone; and
d) the pointing to the stonework was cracked and missing in places. This was caused by weathering over a period of time. When the condition of the pointing deteriorates, cracks and crumbles it can fall out leaving open joints in the stonework which can result in water penetration and dampness.
North (Rear) Elevation of the building -
a) there was evidence of horizontal cracks at the head of the third floor window openings below the projecting roof slab. The cracking appeared to be confined to high level and did not extend to ground level which means it was not related to settlement or ground conditions; and
b) there was evidence of horizontal cracks at sill level connecting the third floor window openings.
(iii) Number 8 Clune Park Street, Flat 3/2
Flat 3/2, 8 Clune Park Street -
a) no internal evidence of rust staining on the ceilings / soffits of the concrete roof slab was observed due to the v-jointed timber boarded suspended ceiling; and
b) no internal evidence of spalling of the ceiling finishes / concrete cover to the embedded reinforcement was observed due to the v-jointed timber boarded suspended ceiling.
West (Front) Elevation of the building -
a) there were open joints at the third floor window lintels and at the north end of the elevation (quoin) adjacent to the gable; and
b) there was an open joint at the head of the stone mullion between the third floor window openings.
North (Gable) Elevation of the building -
a) There was a vertical stepped crack from the rear of the projecting flat roof to the lintel of the third floor window opening.
East (Rear) Elevation of the building -
a) there was horizontal cracking at the junction of the wall head with projecting roof slab and around the lintels of the third floor window openings; and
b) there was a diagonal crack (45 degrees) in the render and brickwork at the junction of 6 and 8 Clune Park Street (where there was a step change in height of the terrace).
(iv) Number 8 Bruce Street, Flats 3/1 and 3/2
Flat 3/1, 8 Bruce Street -
a) there was no internal evidence of rust staining on the ceilings / soffits of the concrete roof slab;
b) there was no internal evidence of spalling of the ceiling finishes / concrete cover to the embedded reinforcement;
c) there were cracks running north to south in the position of embedded reinforcement in the ceiling of the south east bedroom; and
d) there was a diagonal crack in the south wall and within the wall press of the south east bedroom.
Flat 3/2, 8 Bruce Street -
a) no internal evidence of rust staining on the ceilings / soffits of the concrete roof slab was observed due to lowered ceilings;
b) no internal evidence of spalling of the ceiling finishes / concrete cover to the embedded reinforcement was observed due to lowered ceilings; and
c) the north west corner of the lowered ceiling in the north east bedroom was damaged by water ingress.
West (Front) Elevation of the building -
a) the stonework was in a fair condition but with some isolated areas of spalled/damaged stonework;
b) there were areas of lime putty pointing that were cracked or missing in places;
c) the cause of the defects to the stonework was due to the local sandstone used to construct the building being relatively soft. Over time the condition of the stonework and the pointing had deteriorated as a result of natural weathering; and
d) there were vertical cracks in the mortar joints particularly at the third floor level near the North gable.
North (Gable) Elevation of the building -
a) there was a vertical crack at the approximate midpoint of the wall adjacent to the third floor window opening extending down to lintel of second floor window opening;
b) there was a near vertical crack from the chimney head extending down to the head of the second floor window opening;
c) there were 45 degree angle stepped cracks at the East and West ends of the third floor;
d) there was evidence of horizontal cracking at the wall head at the junction with the projecting roof slab; and
e) there was evidence of a vertical crack in the render at lintel of the second floor window opening extending down to the flat roof of the ground floor extension.
North Ground Floor Extension (Gable) Elevation of the building - on 28th July;
a) there were 45 degree (diagonal) cracks in the render at the East end of the roof.
East (Rear) Elevation of the building -
a) there was evidence of horizontal cracking at the junction of the wall head with the projecting concrete flat roof; and
b) there was evidence of stepped cracking following the contours of the window lintels of the third floor.
31 There was cracking in the appeal properties’ buildings at various locations. There was cracking to the gable walls, to the external elevations, and to the internal walls and soffit surfaces.
32 Some cracks in the appeal properties’ buildings had been filled with non-pliable material.
33 Mr Turnbull had not been inside any of the appeal properties. or on the roofs of the appeal properties, prior to preparing his first and second reports for the Defender.
34 The information the Defender had regarding the construction of the roof slabs, at the time of serving the demolition orders, was incorrect.
35 In his first report, Mr Turnbull speculated as to the percentage of each roof that was in a state of “Serious Disrepair” by reason of the “defect” of corrosion expansion.
36 The Defender proceeded to serve the demolition orders on the basis of speculation on the part of Mr Turnbull.
37 The Defender failed to carry out an adequate inspection of the appeal properties prior to taking enforcement action by means of serving the demolition orders.
38 The pattern of supporting steel within the roof slab was not established.
39 Where steel ribs within the appeal properties were exposed and inspected, there was evidence of only surface corrosion. The cumulative effect of the surface corrosion of the steel ribs would not generate enough expansive force for the roof slabs to move.
40 There was no evidence of corrosion expansion of the embedded steel ribs within the roof slabs.
41 The basis upon which the Defender proceeded (corrosion expansion of the steel ribs as the cause of movement of the roof slab) was ultimately not supported by their own expert, Mr Turnbull.
42 The concrete roof slabs in the various buildings within which the appeal properties are situated had in the past moved laterally to varying degrees.
43 The roof, walls and gables of the appeal properties’ buildings had been subject to past movement.
44 The cause of the movement in the roof, and cracking to the walls and gables, was not proved.
45 Prior to service of the demolition orders, and from the date of their service to the date of the hearing, no steps had been taken by the Defender to monitor any movement in the buildings within which the appeal properties are situated.
46 It was not proved the buildings within which the appeal properties are situated had recently moved, or are currently moving.
47 Before advancing his theory of debonding, Mr Turnbull had only examined exposed steel in one small area, at Flat 3/2 8 Clune Park Street.
48 There was no evidence of extensive debonding within the roof slabs of the appeal properties.
49 It was not proved the structural elements of the appeal properties exhibited signs of recent or fresh movement.
Finds in fact and Law
50 As it has not been proved that the appeal properties’ buildings are structurally unstable by reason of corrosion expansion or debonding, it has not been proved the said appeal properties do not meet the tolerable standard as defined in Section 86 of the Housing (Scotland) Act 1987.
Finds in Law;
1. It not having been proved that as at the date of service of the demolition orders, the appeal properties were structurally unstable by reason of corrosion expansion or debonding, or by reason of any other factor, it cannot be said the properties were below tolerable standard in terms of Section 86 of the Housing (Scotland) Act 1987 as at the date of service of the demolition orders, and the Defender was not therefore entitled in terms of Section 115 of the 1987 Act, to serve the demolition orders dated 26th June 2014.
2. It not having been proved that the appeal properties are currently structurally unstable by reason of corrosion expansion or debonding, or by reason of any other factor, it has not been proved the properties are currently below tolerable standard in terms of Section 86 of the Housing (Scotland) Act 1987.
3. There being no proof the appeal properties are currently below the tolerable standard in terms of s86 of the Housing (Scotland) Act 1987, the demolition orders served in respect of the appeal properties on 26th June 2014, fall to be quashed.
Therefore;
Sustains the Pursuers’ First plea in law, repels the Pursuers’ Second plea in law, and in doing so quashes the demolition order in respect of the property at Flat 3/3, 19 Robert Street, Port Glasgow, repels the Defender’s First, Second, Third and Fourth pleas in law, meantime reserves the question of expenses for further submission.
NOTE:
[1] This is an Appeal by Summary Application in terms of Section 129 of The Housing (Scotland) Act 1987 (the Act). The Pursuers seek revocation of a demolition order served on 26th June 2014, or alternatively a suspension of that order. The order and this action relate to property at Flat 3/3, 19 Robert Street, Port Glasgow.
[2] This appeal is one of six appeals all calling before me for a hearing, and all in relation to demolition orders made by Inverclyde Council on 26th June 2014, in respect of properties within the Clune Park area of Port Glasgow. The other cases calling for hearing are cases, reference B435/14 (Flat 3/1, 19 Robert Street, Port Glasgow), B462/14 (Flat 3/2, 8 Bruce Street, Port Glasgow), B463/14 (Flat 3/1, 8 Bruce Street, Port Glasgow), B502/14 (Flat 3/2, 23 Robert Street, Port Glasgow) and B512/14 (Flat 3/2, 8 Clune Park Street, Port Glasgow). All Pursuers were represented by Mr Fairley, senior counsel, and the Defender was represented by Mr Lindsay, senior counsel, in all matters. It was agreed that the evidence led would be evidence in all six cases.
[3] The Defender is the local authority for Inverclyde. In June 2014, it served demolition orders in respect of a substantial number of properties within the Clune Park estate. Two hundred and seventy seven summary applications to revoke those demolition orders were lodged by aggrieved parties. A number of those applications have already been dismissed prior to a hearing. The six actions calling before me for a hearing (I will refer to them as the ‘appeal cases’ and the properties as ‘appeal properties’), are part of the remaining summary applications. The others are presently sisted. It was agreed between parties involved in the various summary applications that the present six applications would proceed to a hearing, with evidence being led in all six actions together. There is no agreement that any decisions in the current applications will be binding on the other sisted applications.
[4] Parties agreed that I should issue a lead judgment covering all six cases, and simply refer to that judgment in the other five cases. This judgment will form the lead judgment.
ISSUE
[5] As part of a regeneration plan, the Defender proposed to demolish five blocks of flats within the Clune Park area. The six properties which form the appeal cases are located within the five blocks. In all six cases, the Defender claims the properties are below the tolerable standard, and in particular, they are structurally unstable. The Defender has served demolition orders stating that to be the case.
[6] A demolition order is made under Section 115 of The Housing (Scotland) Act 1987. Section 115 provides;
“115 Demolition order.S
Where a local authority, on consideration of an official representation or a report by the proper officer or other information in their possession, are satisfied that any building comprises only a house which does not meet, or houses which do not meet, the tolerable standard and that the house or, as the case may be, houses, ought to be demolished, they may, subject to section 119, make a demolition order requiring—
1. that the building shall be vacated within such period as may be specified in the order, not being less than 28 days from the date on which the order comes into operation, and
(b) that the building shall be demolished within 6 weeks after the expiration of that period or, if the building is not vacated before the expiration of the period, within 6 weeks after the date on which it is vacated.”
[7] Demolition orders can be made where a Local Authority is satisfied that all houses within a building do not meet the tolerable standard and that the building ought to be demolished. The Defender made such orders in respect of inter alia, the appeal properties on 26th June 2014.
Definition of a “house” and tolerable standard
[8] Section 338 of the 1987 Act provides that a house;
“…. includes any part of a building, being a part which is occupied or intended to be occupied as a separate dwelling, and, in particular, includes a flat,….”
[9] There are a number of elements of a building that require to be of a satisfactory standard before a building is deemed to be of tolerable standard.
Tolerable standard is set out in Section 86 of the Housing (Scotland) Act 1987 as amended. Section 86 provides;
“86.— Definition of house meeting tolerable standard.
(1) Subject to subsection (2), a house meets the tolerable standard for the purposes of this Act if the house—
(a) is structurally stable;
……… and any reference to a house not meeting the tolerable standard or being brought up to the tolerable standard shall be construed accordingly.
(1A) In construing any such reference, regard shall be had to any Guidance issued by the Scottish Ministers….”
[10] A building falls below the tolerable standard if it is structurally unstable. The Defender claims that the buildings fall below the tolerable standard by reason of the buildings being structurally unstable. The Defender is not claiming the buildings fall below the tolerable standard in any other respect. The issue for this hearing therefore was one of structural stability. The terms of a demolition order do not require specification. The Defender therefore is not obliged within the demolition order to state what has caused any structural instability. Quite simply, if a building is structurally unstable, then in terms of Section 86 it falls below the tolerable standard.
[11] Parties in these appeals however have helpfully focussed the issue. The Defender’s position is that it is deterioration of the structure of the roofs on the buildings wherein the appeal properties are situated (and other buildings in the Clune Park area) that renders the buildings structurally unstable. They go further, and state what they believe is the cause of the deterioration of the structure of the roofs. They say it is caused by extensive corrosion expansion of the roof structure, and/or extensive debonding of the roof structure. They say that corrosion expansion, and/or debonding has caused cracking to the buildings, and the likely consequence of that cracking is that the buildings are structurally unstable. The Pursuers dispute this. They do not accept there is extensive corrosion expansion of the roof structure, and/or extensive debonding of the roof structure. They do not accept there is sufficient deterioration of the roof structures such as to cause cracking to the buildings, and further, whatever the cause of any cracking to the buildings is, such cracking as is present does not render the buildings structurally unstable.
[12] An investigation into the roof structures and of the cracking to the buildings may provide some answers as to the cause or causes of the cracking, its likely progression, and whether or not such cracking is likely to affect the structural elements or the structural stability of the buildings. The principal issue is not what is causing any cracking (although that might be of assistance in determining whether any cracking renders the building structurally unstable) but, whether or not any cracking or other defect that is present, renders the buildings structurally unstable.
Statutory Guidance
[13] Section 86 has been amended by inter alia, the Housing (Scotland) Act 2006. Subsection 1A of Section 86, which was inserted by the 2006 Act, states that in construing any such reference to the tolerable standard, regard shall be had to any guidance issued by the Scottish Ministers. Guidance was issued in 2009; “Implementing the Housing (Scotland) Act 2006, Parts 1 and 2. Advisory and Statutory Guidance for local Authorities”. “Volume 4 Tolerable Standard”, provides guidance on inter alia, the definition of houses not meeting the tolerable standard, the definition of tolerable standard and the definition of structural stability. Chapter 4 deals with structural stability.
“Chapter 4 Structural Stability
4.1. A house meets the tolerable standard if it is structurally stable.
Introduction
4.2. This element of the tolerable standard requires every house to be structurally stable. Instability in the structure of a house is an obvious threat to the occupants' safety.
4.3. This chapter provides Guidance for assessors on how to judge if a house is structurally stable. Assessors should use this advice alongside their own experience and the support of specialists (where necessary) to make decisions.
4.4. As noted in chapter one of this Guidance, staff from a wide range of professional backgrounds assess houses against the tolerable standard. Structural stability is a complex technical area. It is not our intention to provide a comprehensive guide to structural stability here. Instead, our Guidance aims to help housing staff and other professionals who are not structural experts to recognise whether a house is potentially unstable and to identify when to call in a competent professional.
4.5. It would be useful to work jointly with building standards professionals when considering this element of the tolerable standard, as it may be appropriate to take action under s28 or s29 of the Building (Scotland) Act 2003 if a building which fails this element is defective or dangerous.
Legislation
4.6. The tolerable standard has always included the requirement for houses to be structurally stable. The Housing (Scotland) Act 2006 did not change this element of the standard.
Definitions
4.7. Structurally stable: The structural elements of a house should exhibit no signs of recent or fresh movement, evidence of which may indicate to the assessor that the house may be at risk from either partial or total collapse. The main structural elements of a house are:
roof structures and other roof features;
chimneys;
load-bearing walls including external walls;
lintels, sills and mullions, and wall ties;
floors and stairs;
load-bearing beams and columns; and
foundations.
Status of the Guidance
[14] As stated in Chapter 4.4, the Guidance is not an authoritative statement of the law. Chapter 1.15 provides that it is not exhaustive. Further, the Guidance is not binding, but it may be persuasive authority on the construction of the primary legislation. Insofar as the views expressed in the Guidance are inherently persuasive, they may be taken into account in much the same way as those of an academic author. The Guidance may be of assistance if it enables the court to better understand the purpose of the legislation. Ultimately, however, it is the role of the judiciary and not the executive to decide the meaning of the primary legislation.
Appeals
[15] A person aggrieved by a demolition order may appeal against such an order in terms of Section 129 of the Act. Section 129 provides;
“129 Appeals.
S.(1) Subject to the provisions of this section and subsections (2) 1to (7) of section 324 any person aggrieved by—
(a) A closing order made under section 114 or section 119 or a refusal to determine such a closing order;
(b) A demolition order or a refusal to determine a demolition order or a resolution under section 125; ……..
…..may appeal to the sheriff by giving notice of appeal …….
(2) On an appeal under paragraph (a) or paragraph (b) of subsection (1), the sheriff may consider any undertaking such as is specified in relation to a closing order or a demolition order, as the case may be, in section 117 and, if he thinks it proper to do so having regard to the undertaking, may direct the local authority to make a suspension order under that section.
[16] Section 117 of the Act enables a proprietor to give within certain time limits, an undertaking that within a specified period he will carry out such works as will in the opinion of the Local Authority bring the whole building up to the tolerable standard. If such an undertaking is accepted by the Local Authority the Local Authority issues a suspension order suspending the demolition order.
[17] In the six appeal cases the Pursuers appeal against the making of the demolition orders. They firstly crave an order quashing the demolition orders made by the Defender on 26th June 2014, and secondly, in the alternative, ask the court to impose suspension orders in accordance with Section 117 of the Act, suspending the demolition orders to enable the Pursuers to carry out work to the whole buildings of which each individual property forms part, and to bring them up to the tolerable standard, so that the demolition orders can then be revoked. I have no power to impose a suspension order but, in terms of Section 117, I do have power to order the Defender to issue a suspension order.
[18] The procedure in appeals such as this is governed by Section 324 of the Act. Section 324 provides;
“S324 Procedure on applications and appeals to sheriff.
…… (4) The sheriff in deciding an appeal under this Act may make such order as he thinks just.
(5) Any such order shall be final.
(6) In the case of an appeal against a notice given or an order made by a local authority, the sheriff may either confirm, vary or quash the notice or order.”
[19] The first issue in this case is whether or not the properties fall below the tolerable standard. If they do not, the demolition orders fall to be quashed. If they do fall below the tolerable standard, the second issue then is, can the Pursuers, in terms of Section 117, bring the properties up to the tolerable standard, which will allow the demolition orders to be revoked?
[20] Parties agreed that this hearing be restricted to the first issue of tolerable standard, and if it is decided that the properties fall below the tolerable standard, a further hearing would be assigned to consider the issue of undertakings to bring the properties up to the tolerable standard.
ONUS AND BURDEN OF PROOF
[21] The parties very helpfully lodged detailed written submissions following upon the hearing of the evidence, and I am grateful to them for that. The submissions dealt with the onus and burden of proof. The Defender’s position in respect of the demolition orders is that the cause of cracking to the structural elements of the properties is extensive corrosion expansion and/or debonding. Mr Lindsay in his written submissions stated that before the court could sustain the Pursuers’ first plea-in-law and quash the demolition orders, it would require to accept the Pursuers’ evidence that the buildings were structurally stable and met the tolerable standard.
[22] The Pursuers accept that the legal onus of proof lies with them and that the onus is on them to show that the properties are not structurally unstable by reason of either corrosion expansion or debonding. Their position is that if they can satisfy the court on the balance of probabilities that corrosion expansion and/or debonding is not causing structural instability that would be sufficient for the court to quash the demolition orders. Mr Lindsay for the Defender accepted that was the position and accepted that the Pursuers did not need to go any further and prove that the properties were otherwise structurally stable.
ROLE OF THE COURT
[23] There are competing authorities as to the role and the authority of the court in dealing with an appeal such as this.
[24] The Act requires a local authority to be “satisfied” as to certain factual matters before making a demolition order. One view is that I should not substitute my own decision for that of the local authority unless satisfied that the local authority had no reasonable grounds for coming to its decision. (McMikin’s Curator v Local Authority of Carrick (1992) 38 Sh.Ct. Rep149). The prevailing view nowadays is that I am entitled to consider anew whether the statutory basis for making the orders existed. (Flynn v Glasgow Corporation (1938)54 Sh.Ct.Rep.63, McDonald v Midlothian District Council, 1983 J.L.S.S.469). Parties accepted that I am exercising a de novo jurisdiction, and that the issue is to be determined as at the date of the hearing by reference to the evidence which is led at the hearing.
[25] What was initially unclear because of the parties’ positions in their written submissions dealing with the onus of proof was what question was to be considered de novo. In his written submissions Mr Fairley said that if he discharged the onus on him as set out above, I should go further and find that the properties are structurally stable. In discussion he retreated from that position. Following upon the discussions referred to above, parties agreed that the issue for me to consider de novo is whether or not the properties are structurally unstable by reason of either corrosion expansion or debonding, (and the onus was on the Pursuers to show that) and that I did not require to go any further than that. I am therefore entitled to consider anew whether the statutory basis for making the demolition orders exists.
EVIDENCE
[26] Although there is no agreement that any decisions in the six current appeals will be binding on the other outstanding applications the evidence led may be of some interest to other owners within the Clune Park estate who have outstanding appeals, and for that reason I believe it is in the interests of not only those involved in these six current appeals, but also to the other Pursuers that I deal with the evidence in this judgment in more detail than might normally be the case.
[27] The Pursuers led two witnesses;
(a) Mr William Henry Morrison, Chartered Building Surveyor.
(b) Mr Ian Balfour, Chartered Structural Engineer.
[28] The Defender led three witnesses;
(a) Mr William Johnston, Civil Engineer and an assistant manager and material works engineer with Stanger Testing Services Limited.
(b) Mr Paul Hunter, land surveyor and survey manager with Phoenix Surveys (Scotland) limited.
(c) Mr David Thomas Turnbull, Civil and Structural Engineer.
[29] All witnesses provided affidavits and adopted them as their evidence in chief. They also spoke to the various reports they had prepared. A joint bundle of productions was prepared, and all references to productions are references to that joint bundle. The parties, after evidence was concluded, helpfully provided detailed written submissions. Parties also prepared a detailed Joint Minute of Admissions. The joint minute included the findings of a joint inspection of the witnesses, Mr Morrison, Mr Balfour and Mr Turnbull, which took place on 28th July 2015, for the purpose of preparing a Scott Schedule.
Pursuers’ Case
William Henry Morrison’s Evidence
[30] Mr Morrison noted the appeal properties were in various states of disrepair. One had been fire-damaged and parts of the structure had been exposed. In some rooms within the various properties, disruption work had been carried out to expose the steel support ribs embedded in the concrete roof slab. Mr Morrison’s specific observations in relation to the various properties are set out in his original report.
[31] Mr Morrison stated that the buildings had been neglected over the years and that remedial repairs were required. Of the four buildings he inspected, only 8 Clune Park Street exhibited any cracking in the structure, and that was likely to be as a result of localised foundation movement due to defective underground drainage. Mr Morrison’s conclusion was that the buildings were not structurally unstable, and that there were no obvious defects to suggest imminent risk of danger due to instability which would require major repair involving partial or complete rebuilding of the buildings.
[32] Mr Morrison examined the steel roof ribs and found the profile of the steel ribs to be intact. He could not see any delamination of steel due to corrosion.
Corrosion Expansion
[33] Mr Morrison said that whilst corrosion of the embedded reinforcement was a plausible potential explanation for some of the high level cracking that was exhibited, the evidence on site did not support it.
[34] Concrete is rigid when set. On its own, it has limitations on how far it can span between supports. Unreinforced concrete is strong in compression but weak in tension, and without reinforcement is not able to span between walls. In order to cover greater spans it was normal to reinforce the concrete and to have a concrete filler joisted construction. This involved creating a timber formwork into which concrete was poured. Steel ribs (beams) were then inserted at 600 to 1200 mm centres. The ribs provided longitudinal reinforcement. Sometimes additional reinforcement, called transverse reinforcement, was installed running perpendicular to the ribs. Such reinforcement would be other steel plate or wires. Tying wire was also often used to keep the ribs in position while the concrete was poured. Mr Morrison had seen a number of reports regarding the structure of the roof slabs in the buildings in the Clune Park estate. There were reports indicating different thicknesses of steel and reinforcement patterns of the various roof slabs. Of the four tenements within which the six appeal properties were situated, he was unable to categorically state what reinforcement was within each of the roof slabs. The scans contained within the Stanger Testing Services Limited report indicated that there were some transverse, as well as longitudinal, supports. Mr Morrison, however, did not see any transverse supports in either of the exposed ceilings that he had examined. Where the ceilings had been opened up to expose the main ribs/beams, the openings had only been of short length and any transverse supports were not visible. He saw the thick 6mm steel ribs, but did not see any thick rods running perpendicular to them. All he saw was evidence of some tying wire which he thought was about 1 ½ to 2mm thick. He did not see any grid formation of reinforcement, and there was no cracking pattern consistent with such a grid, other than possibly in one top landing of one of the buildings.
[35] According to Mr Morrison, where steel ribs had been exposed, there was no sign of significant corrosion, and the ribs had only some surface corrosion or discolouration. Surface corrosion could have occurred when the ribs were initially inserted into the concrete, as at the time when these buildings were constructed, steel was not galvanised. Loss of section was not evident in any of the ribs seen by Mr Morrison.
[36] Mr Morrison said that if corrosion expansion of the steel was present, he would expect to see a number of indicators of it. He gave evidence of the following;
a. Corrosion is caused by moisture. When he examined the exposed steel, the concrete was not wet and it produced dust when opened up. For embedded steel to corrode it requires to be exposed to air and moisture for prolonged periods. Mr Morrison could see little evidence of water penetration to the buildings. There were isolated areas of dampness due to water penetration. He explained that if the source of moisture was sealed off, the steel would not continue to corrode. He saw evidence of water penetration where the bituminous flat roof covering had failed where it formed an upstand or skirting upright on the roof. Such failure of the roof surface could easily be repaired. An examination of the roofs showed the original surfaces had been overlaid and repaired over the years, presumably to prevent moisture penetration.
b. Ceiling cracking along the lines of the reinforced steel.
That pattern of cracking was not found within all the rooms inspected. If the ceiling was cracking along the lines of the reinforced steel as a result of corrosion, he would also expect to see some corrosion staining on the ceilings along similar lines. That was absent.
c. Where ceilings had cracked due to corrosion expansion one might then expect to see spalling of the plasterwork. That however was also absent.
d. Rotation of the wall heads.
Roof slabs rest on top of the wall heads. The force of the roof slab is greater at the top. If the roof slab is pushed outwards, the top of the wall head, down to the window opening, will rotate outwards. The top of the wall, rather than the whole wall, would move outwards. There was no evidence of significant rotation in the buildings.
e. Significant cracking at the junction of the internal walls and ceilings.
If there had been severe corrosion, he would have expected to have seen horizontal cracking at the junction of the roof slab and partition walls and ceilings. He did not see that to any great extent. Mr Morrison said that if the roof slab was moving, he would expect to see indicators of movement in the internal walls, whether they be load-bearing or non-load-bearing. There were some areas of cracking in the internal walls and ceilings. It was, to a degree, however, much less than he would expect to be caused by corrosion expansion.
f. Deflection of the roof.
The deflection of the roof at 8 Bruce Street was noted to be at the north-east and north-west corners. If the roof had been sagging under its own weight, he would have expected this to have been at a place other than in the corners.
[37] In the absence of the indicators of rust staining and significant internal cracking, he discounted corrosion as the primary cause of the cracking that was evident. If there had been significant movement of the roof slab, he would expect to have seen more horizontal cracking, and rotation of the wall heads, as described in paragraph 5.2.9 of his report.
Cracking
[38] Mr Morrison was referred to a number of photographs shown in his report, and was asked to give his opinion on the cause of cracking that was evident internally and externally. Mr Morrison was satisfied, in the absence of the indicators of corrosion staining and significant internal cracking, that corroding steel was not the primary cause of any cracking in the ceilings.
[39] In the absence of corroded steel reinforcement, Mr Morrison considered alternative explanations for the cracking. The most likely cause, in his opinion, was the expansion of the roof slab due to solar heat gain. When the estate was built the roof coverings were mastic asphalt. It was hot-poured onto the roof surface. Asphalt is a dark coloured material which absorbs solar heat gain leading to thermal movement of the roof slab. Such roofs have, in some cases, been superseded by bitumen felt. The dark mastic asphalt absorbs more heat than felt and the material rises to a much hotter temperature than the ambient temperature. Concrete and steel react differently once subjected to solar heat. The concrete cover on the underside of the steel ribs is thin and forms a weak spot in the roof slab construction, and is subject to moisture and temperature changes. An increase in temperature causes the concrete to expand and the roof slab to move. This results in cracking forming at the positions of the embedded steel reinforcement giving the pattern cracking noted on the ceiling finishes in a number of the rooms. Cracking occurs at the weakest part of the building, and in the roof slab that would be the junction of the embedded steel and the concrete. As the slab expands, the steel bars expand and the movement within the roof slab causes cracks at the weakest points, which would be the shallow concrete covering under the bar at the ceiling. In winter, the internal surface is warmer than the external surface. This would be the reverse in the summer. Mr Morrison’s opinion was that thermal movement was the most likely cause of the horizontal cracking in the ceilings.
[40] Mr Morrison was asked about step cracking in the external cross walls. He suggested that movement showed the external walls had moved out and had pulled the internal walls with them. The external walls had moved due to a combination of factors, such as thermal movement or inadequate support. The walls were ten to twelve metres long and were not free-standing walls.
[41] Mr Morrison explained that all buildings constantly move. This is due to a number of features, including variations in temperature and moisture. Cracks can occur in non-structural elements of a building such as non-load-bearing partition walls. Such variations result in relatively small movements. Such small movements can cause cracking in the walls and that usually occurs at the weakest part of a building, which is often at windows and doorways, or where the thickness of a building changes. Modern buildings now incorporate movement control joints and these were designed in a structure to accommodate changes due to thermal movement and moisture content. The movement control joints were filled with unpressable material. Cracks that have been repaired in the past can reappear if the repair has not been carried out with appropriate materials. If historic cracks were filled with a material that was incapable of dealing with such a mortar based product, then the subsequent small movements of a building would lead to re-cracking at the mortar repair areas. If the repairs were undertaken with a mastic or polysulphide material that had some elasticity, that would result in a more effective repair and may avoid re-cracking. Re-cracking would be a normal feature of a building where cracks had been repaired with a rigid material. Cracking could be caused by chemical changes, other structural factors such as timber decay, and over loading of walls and lintels. Each of these would not necessarily render a building structurally unstable. Mr Morrison said that cracking in a building had to be investigated to decide if the cracking made the building structurally unstable.
[42] A house with only historic cracking would not normally be below tolerable standard on the ground of structural instability. It was important to establish if the cracking was historic or recent. Mr Morrison was of the view from his own experience that the majority of the cracking in the appeal properties appeared to be historical. A fresh crack looked clean and fresh, whereas an external historical crack looked more weathered. He accepted that some cracks had been filled and had reappeared. That was not a reason for concluding that the buildings were still moving significantly, but was more likely to be explained by the original cracks being filled with non-pliable filler. There were a number of ways to monitor cracking, the more modern and accurate method being to install calibrated tell-tales on either side of the cracks. These “tell-tales” are clear overlapping Perspex sheets with grid lines. Using these, a building could be monitored normally over a period of 12 to 18 months to show any movement in the building.
[43] Mr Morrison was asked to assess the likely cause of the external cracking. The buildings subject to this action were built in the early 1900s. They did not incorporate movement control joints. It was expected in buildings of this nature, due to the length of the walls, there would be cracking at the weakest part of the walls, such as the doors and window openings or where the thickness of the walls changed.
[44] Mr Morrison gave a number of possible causes of the cracking, including the absence of movement control joints in external front and rear walls of considerable length, cyclical change in temperature, and moisture content. The cracking was likely to be due to a variety of causes, one of which was thermal movement. He accepted that thermal movement was not a cause of all the cracking. He did not accept Mr Turnbull’s view however that thermal movement was not a possible explanation for some of the cracking in the building. He was satisfied that none of the cracking suggested the buildings were structurally unstable.
[45] In dealing with the Verticality Report by Phoenix Surveys (Scotland) Limited, Mr Morrison stated that the report was based on a one-off inspection and therefore it could not determine if the buildings or walls were moving. He did not consider the degree to which the buildings were off-plumb to be of any concern, or to affect their structural stability. At 8 Bruce Street, the building was off-plumb at the front by 48 mm. The building, however, was ten to twelve metres high, and there were no standards for such matters when these properties were built. He believed the walls being out-of-plumb was contributed to by the lack of adequate lateral restraint of the external walls, to the cross-walls and to the roof slab. The wall was extremely high and was susceptible to wind loads, and the wall needed support from cross-walls. The movement in the roof slab at ten to twelve metres in height was insufficient to cause movement at lower levels. If all the movement was at roof level, he would expect to see cracks at high level, i.e. the top floor, and at window head level, rather than window sill level. It was noted that each floor level showed the walls being out-of-plumb. It was not unreasonable to expect the outer walls to move out slightly over a period of one hundred years. A contributory factor would have been the possible lack of lateral restraint at floor levels. If there was evidence of displacement and rotation at the roof level that would indicate the roof slab was moving. The cause of movement would then require to be identified. There was, however, no cracking across the entire ceiling of the buildings.
Debonding
[46] The issue of debonding, which had been raised by the Defender late in the day and therefore was not specifically covered in either of Mr Morrison’s reports or in his affidavit, was put to Mr Morrison.
[47] Mr Morrison accepted that the exposed metal ribs he had viewed did have some evidence of gaps between the ribs and the concrete. He was adamant there was no evidence of anything other than surface corrosion on the steel. If there had been corrosion, then the bar would have expanded to take up the small air gaps present. It was put to Mr Morrison that the gaps between the steel ribs and the concrete indicated that the bond between the concrete and the steel had been lost. Mr Morrison did not see any evidence of that. He had noted that to be the position in his affidavit and considered the gaps to be either due to poor compaction of the concrete at the original date of construction when the concrete was poured; by initial shrinkage and separation between the dissimilar steel and concrete materials over the decades; or as a result of additional shrinkage of the concrete due to carbonation of the cement by atmospheric carbon dioxide. He would expect to see more pronounced cracking of the ceiling if there was debonding and the roof slab was dropping under its own weight.
[48] There was evidence of deflection on the top surfaces of the roof and there was ponding of rainwater. Deflection of roof slabs on a building of this age was not, however, abnormal and could be simply caused by the method of screeding applied to the roof in order to provide drainage.
[49] It was put to Mr Morrison that the debonding process started with deflection of the roof slab. He did not accept that that was necessarily the case. He accepted that carbonation reduced the protection against rust, but also caused additional shrinkage of concrete. He did not accept Mr Turnbull’s conclusion in paragraph 11 of his Affidavit that the steel was no longer bonded to the concrete over its entire area. He accepted there was evidence of debonding in one of the steel ribs that was exposed to him and in a limited area of that rib. The other rib he viewed had not been opened up to full height and it was difficult to say if it had debonded. Even if there were gaps at the side of the steel bars, the top edge was still in contact with the concrete and provided support.
[50] Mr Morrison stated that the joint inspection confirmed the roof coverings of the six flats inspected were generally watertight (other than in isolated areas) and where exposed, the embedded steel reinforcement of the roof slabs was not severely corroded and therefore could not be the root cause of the cracking in the buildings.
Structural Stability
[51] Mr Morrison said the structural elements of a building are those parts which carry and distribute load in addition to their own self-weight and include the foundations, walls, roofs, floors and stairs. Stability is the resistance of a structure to sliding, buckling, excessive deflection or overturning. The structure of a building is fundamental to ensure the safety of its users and of the general public. Mr Morrison stated that there were a number of definitions of the term “structural stability” but they all generally had the same meaning. He would refer to the statutory Guidance when considering structural stability in residential property. The Guidance stated that an assessor, in considering structural stability, should look for reasonable signs of potential instability in any structural element of the building, as a house if structurally unstable would normally show signs that it is moving, or that a structural element is likely to fail. In referring to the Guidance and to his report, Mr Morrison said that it was the house that must be at risk of partial or total collapse. Individual structural parts of the building may show signs of partial, or total, collapse but, in his opinion, that did not render the building as a whole structurally unstable.
[52] Mr Morrison referred to Chapter 4.7 of the Guidance, and stated that having examined the six properties his opinion was that they were all structurally stable. Fresh cracking is highlighted in the Guidance as an indicator of possible structural instability and assessors should look for evidence that cracks are fresh. The Guidance stated that a house with only historic cracking will not normally be below tolerable standard on the ground of structural instability. A house showing fresh cracking may be below the tolerable standard. There may however be fresh cracking in the building but that might indicate no structural instability.
[53] Although the appeal buildings had a number of cracks, none of them gave him cause for concern, and none of them were likely to render the buildings subject to partial or total collapse. He was of the view that none of the buildings required major repair that involved partial or complete rebuilding of the buildings. He stated, however, that if no remedial works were carried out to the buildings that might lead in due course to failure of the structures. Although the definition of structural stability does not impose a time frame, Mr Morrison, in his evidence, said that when considering structural instability of the structural elements of a building, or of the building itself, he would often refer to structures being at ‘imminent’ risk of either partial or total collapse. By ‘imminent’ he suggested six months to one year. That would be on the basis that the building was not subject to repair within that period.
[54] Mr Morrison said that all buildings had the potential to be structurally unstable if not maintained. Much would depend on their construction. If there was water ingress, then timber might decay and that could lead to failure, for example, of roof or floor timbers. A failure of a floor would be a failure of a structural element of the building, but it would not affect the overall stability of the building. A structural element could therefore be liable to partial collapse, without the building as a whole being so.
[55] Mr Morrison was specifically asked his opinion on whether or not a building which was considered safe for the next five to ten years would be considered structurally stable. He stated that it would, and if the building was structurally unstable then it must be considered unsafe. An unsafe building, however, was not necessarily a structurally unstable building. Falling stonework could render a building unsafe, but the wall from which the masonry fell could still be stable. Structural elements of a building could have defects and be at risk of failure, but that did not necessarily mean that the building was at risk of partial or total collapse.
Iain Balfour’s Evidence
[56] Mr Balfour was instructed in early 2014, by some of the owners of properties within the Clune Park estate, to inspect various properties within the estate, to establish any structural defects within the properties, and to determine if the overall structural stability of each building had been compromised by any such defects.
[57] Mr Balfour’s report was based on an initial non-disruptive visual inspection carried out on 26th March 2014 and 8th April 2014, and a disruptive survey of seven top floor flats on 29th May 2014. Only two of the flats that were subject to disruptive surveys are properties subject to these appeals, (B434/14 Flat 3/3 19 Robert Street, and B463/14 Flat 3/1 8 Bruce Street). The disruptive surveys involved removing a local area of ceiling finish and forming a hole in the underside of the concrete slab in each of the properties, thereby exposing a steel rib. At the time of his inspection, Mr Balfour had seen the first ATK Partnership report and was able to consider Mr Turnbull’s initial assumptions and findings. At the time of his inspections and report Mr Balfour had been asked in particular to consider whether or not he saw evidence of corrosion expansion in the roof slabs.
[58] As well as providing a report on his findings, Mr Balfour contributed to the preparation of the Scott Schedule. Mr Balfour said that when preparing the Scott Schedule, more often than not Mr Turnbull’s opinion differed from the opinions of Mr Balfour and Mr Morrison, as Mr Turnbull maintained that all the cracks were caused by horizontal movement of the roof slab due to corrosion swelling of the steel reinforcement. At the point of the joint inspection in order to prepare the Scott Schedule, Mr Turnbull had not raised the issue of debonding.
Internal Inspection
[59] For the purposes of his report, Mr Balfour inspected the properties internally. In each of the seven top floor flats he inspected, a steel reinforcing rib was exposed and assessed for corrosion. The bars were exposed by an owner using a hammer and chisel. In only one of these seven, which was not one of the appeal properties, was there corrosion which reduced the cross-sectional area of the steel, and that was by only 1 – 2%. Mr Balfour believed the corrosion would have been as a result of historical water ingress. No current water ingress was noted and no corrosion staining was noted. There was nothing to signify that the extent of the corrosion was causing structural problems within the slab. There was no tension cracking or spalling concrete, and no horizontal expansion, as was thought by Mr Turnbull.
[60] In the six remaining properties where the steel plates were exposed, only minor surface corrosion was evident which was in no way detrimental to the strength of the steel, and was likely to be as a consequence of condensation from thermal gradients between the internal and external surfaces. In each of the properties there was evidence of hairline cracking in the concrete soffit (ceiling) running along the lines of the steel ribs. Mr Balfour concluded the cracking was merely cosmetic, for reasons set out in his affidavit and report, and was not enough to cause the expansion of the roof slab as claimed by the Defender.
[61] With regard to corrosion staining of ceilings, Mr Balfour stated that for that to be evident there needed to be sufficient water percolating down through the roof onto, and past, corroded metal and onto the ceiling. In cross examination, Mr Balfour accepted that recent Artexing of a ceiling could mask the signs of staining, but he did not think that any of the Artex in the properties he visited was recent. He noted some minor hairline cracking on the Artex and therefore water could have percolated through that. He confirmed that there was no evidence of any staining in the concrete in the areas where the concrete had been opened to expose the steel beams, and those areas were perfectly dry. There was no evidence that any of the appeal properties had been artexed.
External Inspection
[62] Mr Balfour noted cracking of the external elevations and gables and gave a number of possible causes, including chimney flues. He was of the view that any cracking was largely historic, and by that he meant anything that might be older than say two years (but that was very much a flexible timescale). He came to that view based on his experience and on his examination of the cracks. He said the only definitive way of ascertaining the age of cracking was to monitor the building over a period to see if it moved. His first impression of the buildings, looking at them, was that they looked plumb. His evidence in that regard however had to be considered alongside the results of the verticality survey, which showed the buildings were out of plumb. Internally, there was no significant cracking or large gaps between the internal cross walls and the external walls, and the walls did not appear to be moving. Mr Balfour seemed unconcerned with the results of the verticality survey. He did not consider that the walls appeared to be moving at present and said the walls could remain quite happily out of plum for many years.
[63] Mr Balfour concluded that Mr Turnbull’s assumption that the roof was constructed using pre-cast concrete units with multiple internal reinforcing steel bars was incorrect. He did not agree with the assumption that the internal reinforcing steel was corroding and causing horizontal movement, as he only saw evidence of surface corrosion of the steel. He noted Mr Turnbull’s report attributed twenty five structural defects to the corrosion of steel reinforcement and the horizontal movement of the slab. He acknowledged that Mr Turnbull may not have been afforded the opportunity to carry out intrusive investigations prior to preparing his report.
[64] Mr Balfour’s opinion was that the assumption the internal reinforcing steel was corroding and causing horizontal movement within the concrete was inaccurate, as the concrete did not contain significant amounts of reinforcing steel, and the steel that did exist was relatively free from any major corrosion such as to cause the expansion relied upon by the Defender. The surface corrosion had not altered the profile or section of the bars that he inspected in the appeal properties. The roof slabs were considered to be structurally sound, with no expansion of the slabs observed, and therefore no outward pushing of the tenement walls.
[65] Mr Balfour accepted that based on his inspection of a number of properties within the estate, and having considered the results of the verticality survey, it was evident that some degree of outward wall head movement had occurred over the lifespan of the properties. He believed however that the movement had occurred due to varying factors, all as set out in Mr Morrison’s report. He accepted that cracks in the external walls did exist, but was of the view that the cracking appeared to be historic, and would only get worse through water ingress and freeze/thaw actions during the winter period. If water ingress was prevented, then, in conjunction with local repairs, the walls were likely to remain stable.
[66] Mr Balfour’s conclusion was that it was clearly evident that local movement of the walls had occurred, rather than a global failure.
Debonding
[67] Mr Balfour said the concrete was well bonded to the steel in the two appeal properties that were exposed. Some gaps would naturally have been created by the process of exposing the steel bars for inspection by the use of a hammer and chisel, but his impression was there were no voids and the concrete seemed well bonded to the steel. He did not see any evidence of widespread debonding. He said it would have been very hard to see evidence of widespread debonding unless there were significant gaps at the base of the steelwork where the concrete had pulled away from the steel. The cracks he saw were hairline. The only definitive way of checking for widespread debonding would be to carry out more exposure works.
[68] Mr Balfour’s opinion was that the buildings within Clune Park estate were not structurally unstable, and there was little or no evidence of steel corrosion sufficient to cause the expansion of the concrete roof panels and outward movement of external walls as a consequence. Mr Balfour believed the buildings could remain structurally stable for a number of years even without any repair works being carried out.
Defender’s Case
William Johnston’s Evidence
[69] Mr Johnston spoke to the terms of the report from Stanger Testing Services Limited. On the instructions of the Defender, on 5th June 2014, Stanger Testing Services Limited tested five locations within the Clune Park estate. Their inspections included inspections of the roofs. None of the properties inspected were the appeal properties, although Flat 3/1 8 Clune Park Street was within the same building as the appeal property, Flat 3/2 8 Clune Park Street (Ref B512/14). No explanation was given as to how the particular properties had been chosen. Each roof slab was inspected using a hilti-feroscan, which was essentially an electro-magnetic cover meter (a metal detector). That instrument is able to detect steel reinforcement within concrete and determine the amount of concrete cover, thereby obviating the need to open up the concrete. The more concrete cover there is the less chance there is of steel reinforcement being impacted by corrosion. At each location a breakout of the concrete was done to identify the depth of concrete and reinforcement detail.
[70] All the properties inspected had the same roof structure. It was found that reinforcement steel ribs, 7 mm x 75 mm, and spaced 600 mm apart, spanned the width of each room. They lay on top of 6 mm O-bars, spaced between 400 and 600 mm apart, and they spanned the length of the room. The concrete cover to the first layer of reinforcement was found to range from 5mm to 25 mm. The roof slabs were confirmed to be of lightweight furnace bottom ash in situ concrete with a total depth recorded to be 110 mm. In the appeal property at 8 Clune Park Street, the rear bedroom was tested. This had a vertical rib cover of 10 to 15mm with a vertical rib size of 7mm by 75 mm, and a horizontal bar cover of 5mm to 10mm with a horizontal bar diameter of 6mm.
[71] The concrete was tested for Depth of Carbonation. It was found that the entirety of the areas drilled through were fully carbonated from top to bottom of the roof slab.
[72] The concrete was also tested for chloride content, and it was found to contain negligible traces of chloride. The higher the chloride content, the greater the risk of corrosion in the reinforcement. There was therefore little risk of corrosion from the chloride.
[73] The report from Stanger Testing Services Limited concluded by saying that the break-outs which had been created in the concrete, exposed steel ribs which showed signs of significant surface corrosion. The 6 mm O-bars at several locations were found to be fully corroded and crumbled and broke off from the concrete. Mr Johnston was unable to specify where those locations were, and it could not be said they were at 8 Clune Park Street. He did not mention any wire loops.
Paul Hunter’s Evidence
[74] Mr Hunter is a land surveyor and survey manager with Phoenix Surveys (Scotland) Limited, a company he formed in 2000. He has 32 years of experience in land surveying. He was instructed by the Defender to carry out verticality surveys at twenty nine locations in respect of twenty buildings within the Clune Park estate. His remit was to measure the verticality of the buildings and to report his findings. He was not instructed to offer any opinion as to the state of the buildings. The buildings within which the appeal properties are located were surveyed. He said he was instructed to take additional measurements towards the wall head, on the top of the façade. The verticality report dated 23rd March 2015 comprises Productions 12 and 13. Despite saying he could offer no comment or offer any opinion as to the state of the buildings, his role being to simply record the data, Mr Hunter said he was surprised by the results obtained, as he had not been aware from visual inspection how much the buildings were leaning out. From his experience he concluded the buildings were out of plumb ‘an awful lot’. In detailing his experience of surveying tenement buildings, Mr Hunter described how he had monitored many tenement buildings for movement. Monitoring would normally be carried out over several months, although in one case he had been monitoring a building for five years. That type of work was quite different to his instructions in this case, where his instructions were to carry out a one-off spot measurement of the buildings. He had not been instructed to monitor any movement in the buildings. He therefore was not able to say if there was any current movement in the buildings.
David Turnbull’s Evidence
[75] Mr Turnbull previously worked for the Defender for fourteen years. He has considerable experience of working with tenemented property and government refurbishment schemes. He said he had extensive experience of dealing with reinforced concrete and had come across many such floors that had become corroded over time.
[76] Mr Turnbull had prepared an initial report, Production 9, dated 5th December 2013, revised 19th February 2014 and further revised 14th March 2014, and a supplementary report, Production 10, dated September 2014, and revised April 2015. He participated in the preparation of the Scott Schedule, Production 24. He had also sworn two affidavits dated 17th December 2015 and 15th January 2016.
[77] Mr Turnbull was instructed by the Defender. In evidence he was vague as to the terms of his initial brief from the Defender asking him to prepare his initial report. He said he was not given written instructions and was simply asked to do a walk-round survey and to give a report on the overall structural condition of the properties. He had limited access to the properties. He stated he did not know the purpose of his inspection, or of his report, and only became aware of their purpose when the issue of tolerable standard was raised with him. He could not recollect when that was.
[78] Mr Turnbull accepted that it was quite possible he had not entered any of the properties by the time he had prepared the final version of his first report in March 2014, and accepted there was nothing in the report to indicate that. He accepted that he had not been on the roofs of the properties and had only looked at photographs provided by the Defender. The first time he was inside any of the appeal properties was in July 2015, when he was present for the purposes of preparing the Scott Schedule. He maintained that it was not essential to physically examine the properties in order to prepare his report, and that he was able to draw conclusions from his limited inspections.
[79] Mr Turnbull said that when he initially inspected the buildings in the Clune Park estate he thought the ceilings were all of pre-cast concrete construction. He came to that conclusion because he saw linear cracking on the ceilings, all following the same lines. It proved, however, after a disruptive opening of the ceilings some time later, that the slabs had been poured in situ.
[80] In his first report, Mr Turnbull noted various defects in various properties, three of which were appeal properties. In particular, he noted external cracking to the properties; mainly to the gables and to some front and rear elevations, and some internal cracking within some common closes. With regard to each incidence of external cracking, Mr Turnbull attributed the cause to corrosion swelling of the roof slab.
[81] As evidence of corrosion expansion Mr Turnbull noted, (1) spalling of the concrete roof slab, (2) staining from the steel reinforcement where the slab projected over the wall heads externally, (3) cracking of the stonework at the gables increasing in width as the cracks rose nearer to the roof, and (4) horizontal cracking above third floor window level - he said this was caused by the horizontal pressure from the swelling roof slabs causing the top two or three courses of brickwork and lintels to be pushed outwards.
[82] Mr Turnbull concluded that the cause of these indicators and of the principal defect was corrosion swelling of the precast concrete roof slabs. He considered that the defect affected more than 20% of each roof. He believed the roof and upper walls would become unsafe in five to ten years. He concluded in his first report that the roof structures were spreading, with the outer ends of the roofs moving apart. There was evidence that the movement was continuing and would continue until failure occurred, either by collapse of cracked masonry or collapse of a roof slab.
[83] Mr Turnbull’s second report, Production 10, was prepared after he had been able to consider the Stanger Testing Services Limited report and Mr Morrison’s report. His second report again dealt with a number of properties which are not appeal properties. His conclusions were therefore partly based on evidence he had gathered from Stanger Testing Services Limited in relation to properties that were not the subject of this hearing. Mr Turnbull maintained his view that the cause of the principal defect was corrosion swelling of the concrete roof slabs, and for the same reasons as he had detailed in his first report. He provided a calculation of the possible spread of the roofs based on the number of reinforced steel ribs that would be corroding within the concrete. He noted at paragraph 6 that, “With few exceptions these roofs are now seriously weakened due to corrosion of the steel beams. Such roofs require either to be demolished or strengthened.”. He further noted, “that distribution reinforcement is heavily corroded and that main bars are corroding and causing swelling but are not significantly weakened structurally.”.
[84] Mr Turnbull set out in his report an analysis of crack patterns. Having considered flue lines and cracking on single storey extensions, he concluded the cracks were as a result of a mechanism in the roofs of corrosion swelling exerting an outward horizontal force and “that no other mechanism could explain the defect.”. Mr Turnbull’s conclusions on the cause of the defect had not changed from his first report.
[85] Mr Turnbull said in his reports that it was difficult to predict the lifespan of the buildings. He opined that if no work was done to the properties, sections of the roof and upper walls would become unsafe in five to ten years. As this appeared to me to mean the buildings were considered by Mr Turnbull to be safe for approximately that period, in advance of what was likely to be a lengthy hearing I asked the Defender if it could clarify Mr Turnbull’s position. I did wonder how a building could be considered safe and yet be structurally unstable in terms of the Guidance. Mr Turnbull provided an affidavit dated 17th December 2015, wherein he stated that he remained unreservedly of his view as set out in his report. He explained that if no work was undertaken in respect of the roofs within the Clune Park estate, leaks would establish, accelerating the corrosion of main ribs and secondary bars within the roof slab. This would lead to the walls being pushed outwards by the spreading of the roof slab, such that spalling of brick or masonry wall heads was likely. That was clearly stated by him in his reports. He went on to say that loss of concrete or masonry could lead to injury. In the circumstances he considered the buildings unsafe and dangerous. He went on to say, that when he referred to the buildings as being unsafe, he meant dangerous. He reiterated his view that the buildings would become dangerous or unsafe in five to ten years. He said that was entirely distinct from his view that the buildings were currently unstable.
[86] Mr Turnbull’s second affidavit was dated 15th January 2016, approximately ten days before the hearing, and that affidavit was to form his evidence in chief. In paragraph 11 thereof, Mr Turnbull introduced, for the first time, the principle of debonding, and its possible cause of a roof collapsing in on itself. He had previously mentioned roof collapse at paragraph 8.2 of his second report, but that was in the context of corrosion expansion and the reduction of the roof’s ability to sustain tensile forces. He referred to calculations contained within a schedule to his affidavit, and he referred to deflection of the roofs as evidence of debonding. He said the findings within the Scott Schedule and the disruptive surveys both supported debonding as a process affecting the roofs.
[87] In his oral evidence Mr Turnbull began by saying the buildings were structurally unstable in the sense that there were signs of movement and, more recently, it had been found that the steel was not fixed to the concrete. That caused a risk of structural failure. He dealt with cracking of the stonework and brickwork gables by repeating what was in his reports, and he maintained his view that the cracking was recent and progressive.
[88] Mr Turnbull dealt with the various mechanisms that he found within the appeal properties.
Corrosion Expansion
[89] Mr Turnbull’s conclusion in his reports was that corrosion of the steel had caused the roof slabs to expand. He explained that there were two forms of steel in the roof slabs; filler joist bars (the steel I-beams/ribs), and steel/wire loops of 6mm diameter which were tied to the ribs.
[90] There was some confusion as to whether the ribs were additionally supported by other cross-beams of steel. The Stanger Testing Services Limited scans and report had shown steel running at right angles to the ribs. Mr Morrison, in his evidence, had said that sometimes additional transverse reinforcement was installed to run at right angles to the ribs. Mr Turnbull explained that he and Mr Morrison were effectively talking about the same thing. The ribs were held in place by steel loops which were tied to each rib and joined to the next rib, and were designed to keep the ribs in place while the concrete was poured. He said the greatest risk of corrosion expansion of the roof slab was caused by corrosion of steel loops within the concrete, rather than the steel ribs. The steel/wire loops were corroding to a greater extent than the filler joist ribs.
[91] He explained that the steel loops had another function, which was to help support the concrete once it was in place. Without such loops the concrete would only be sitting on the flanges of the ribs. The concrete would therefore bond on to the loops of wire running between the ribs. Mr Morrison said however that he had not seen any reinforcement rods running at right angles to the ribs, and that all he saw in the small areas that were opened up was evidence of some tying wire which he thought was about 1 ½ to 2mm thick. Stanger Testing Services Limited had estimated the steel to be about 6mm.
[92] During the course of Mr Turnbull’s evidence, Mr Fairley objected to evidence being led from Mr Turnbull that corrosion expansion of the wire loops was the main cause of movement of the roof slab. Mr Turnbull had been asked if surface corrosion of the steel ribs would generate sufficient expansive force to move the roof slab. Mr Turnbull conceded it would not, but then said the main problem he saw when he inspected 8 Clune Park Street, was extensive corrosion of the wire loops, and that was the main problem for the roof slab. Mr Fairley claimed that had not been the case on record. The Pursuers had always believed the Defender’ position was that the steel ribs had corroded, thereby causing the roof slab to move. There seemed to be some general confusion with the terminology of the different steel components within the concrete roof slab. Although it was agreed by parties that I should hear evidence on the issue under reservation, Mr Lindsay agreed not to explore further the claim that corrosion of the steel loops, rather than the steel ribs was the main cause of corrosion expansion of the roof slab. Ultimately Mr Fairley was content for the evidence heard under reservation to be admitted into the evidence.
[93] Mr Turnbull said there was some uncertainty between the parties as to whether or not the roof comprised of two or three steel elements. One possibility was that the roof comprised of steel ribs (I-beams) measuring 75 mm x 6 mm. They sat on top of 6 mm distribution bars, which ran at right angles. A third element comprised of wire loops going around the adjacent steel ribs holding the ribs in position. The second possibility was that there were steel ribs (I-beams) measuring 75 mm x 6 mm, with wire loops holding them in place, but with no 6 mm distribution bars underneath. Mr Turnbull preferred the latter configuration as representing the roof structure within the properties. He noted that Mr Balfour had not seen any distribution steel, as had been reported in the Stanger Testing Services Limited report.
[94] Mr Turnbull’s opinion on the supportive effect of the steel loops was unfortunately not explored in the evidence of the Pursuers’ witnesses in any great detail. Presumably that was because the existence of ‘steel loops’ was unclear in the Defender’s pleadings, had not been mentioned clearly in Mr Turnbull’s reports, and was therefore inadvertently sprung on the Pursuers at the hearing.
[95] Mr Turnbull was referred to the specific appeal properties he examined, 19 Robert Street and 8 Clune Park Street. In one he saw more than just surface corrosion of the steel rib whilst in the other only surface corrosion. There was no de-lamination and no separation of the concrete and steel. He said however he could conclude that over the twenty ribs or so in the ceiling there was corrosion present, which either would be surface or moderate in extent. He stated that where cracks in the ceiling had been seen, but no disturbance, that would likely be representative of surface corrosion. He stated that the two areas exposed would be representative of all the ribs in all four buildings, some of which would be more corroded and some less so. Mr Turnbull concluded that there was expansion corrosion throughout the whole Clune Park estate.
[96] Mr Turnbull stated that cracks in the ceilings in all six flats, diagonal cracks in the closes and in some flats near the wall head, some separation expansion between the external walls and the cross-walls (most evident within the closes), all indicated expansion of the roof slab. He noted an increase in width of the cracks at greater height, suggesting the wall was rotating out in a clockwise direction from the top of the windows. Mr Turnbull explained that if steel in the slab corroded, it formed cracks on the line of the steel bars within the ceiling. The bars were then pushed out and that caused the walls to shear at a 45-degree angle.
[97] Mr Morrison’s explanation of some of the cracking being caused by solar or thermal movement was put to Mr Turnbull. He said that could not account for areas of the properties where there were no flues, or where areas of the flat roofs were shaded by other buildings where the heating differential in the roofs would be minimal.
Debonding
[98] Mr Turnbull said debonding could be caused by shrinkage of the concrete, or corrosion expansion of the steel pushing the concrete away from the steel. He said wire loops were placed every 300 mm along the beams and were looped round the beams. Corrosion of the wire loops would push the concrete away from the steel beams.
[99] I asked Mr Turnbull about the basis of his evidence on debonding. This was based on only his inspection of Flat 3/2, 8 Clune Park Street. One part of the ceiling was exposed in the bathroom. He saw evidence of debonding at two locations. He recollected that there were two references within the Scott Schedule to air gaps being present. He said that the debonding had led to there being no composite slab of concrete and steel and that there was approximately 500 to 700 kilograms of concrete sitting over a span between the ribs. That reduced the capacity of the roof and caused the roof to deflect.
[100] Under cross-examination, it was put to Mr Turnbull that his theory of widespread corrosion expansion could not be correct if there was widespread debonding, and that the two could not co-exist and be the cause of a moving roof slab. Mr Turnbull said he had been drawn to that same conclusion and that was when he concluded that, in fact, it was corrosion of the steel wire loops that was creating an outward force on the concrete caused by expansion. He said that where there was a gap at the steel ribs caused by debonding, corrosion expansion could only be linked to corrosion of the loops. Mr Turnbull eventually accepted that corrosion expansion and widespread debonding were inconsistent with each other, and if there was widespread debonding, there would be no corrosion expansion of the same material. Where there were different levels of moisture, there was likely to be corrosion expansion in parts, and debonding in other parts.
Deflection
[101] Mr Turnbull noted significant ponding on the roof indicating much greater deflection than the norm. One of the roofs had four areas of deflection that corresponded with the four rooms underneath. That showed the roof had been unable to cope with the weight of the slab, and that was evidence of widespread debonding.
Structural Stability
[102] Like other witnesses, Mr Turnbull’s evidence in chief was contained within his affidavits. In his second affidavit, Mr Turnbull dealt with structural stability in some detail, and at paragraph 10 thereof he referred to the definition as contained in Chapter 4.7 of the Guidance. He noted the Guidance stated that houses should not exhibit signs of fresh movement. His opinion was that the appeal properties did show such signs. He said;
“These are all signs of fresh movement. In my view the roof structures and other roof features are at risk from either partial or total collapse. The degree of movement in the external walls would not suggest complete collapse of the wall, but localised spalling of concrete or masonry, as has happened will now manifest itself. This spalling or falling of masonry and concrete is the partial collapse of one of the structural elements, being the roof.”
[103] Mr Turnbull’s position was that a ‘total collapse’ of a building could be as simple as a block of concrete falling from an overhang. That was not a view supported by the Defender’s counsel.
[104] Mr Turnbull interpreted the Guidance as stating that recent movement of a building was a sign that a building was structurally unstable. Addressing the issue of structural stability, Mr Turnbull stated that the shedding of concrete would make a building unsafe, and that may be a matter for the dangerous building section of the Council. Shedding of concrete was an indicator of partial or total collapse of a building. When asked if a building could be structurally unstable and yet be safe, his evidence was confusing. Mr Turnbull’s interpretation of the legislation was that a building that was stable would not be moving.
[105] Mr Turnbull’s conclusion in his first report was that if no work was done to the buildings, the roofs and upper walls would become unsafe in five to ten years. There was a difference between the safety of a building and its structural stability. The buildings were subject to the concrete spalling and that was due to corrosion expansion. The extent of the frequency of that was not sufficient to make the building unstable, but if no work was done, there would be an increase in the frequency of the spalling which would render the building unsafe and unstable. He accepted however that a house that was at risk of partial or total collapse could not be considered safe. It was put to him that if a building could not be considered safe if it was at risk of partial or total collapse, and if he had said the appeal properties would be safe for five to ten years, did that mean the appeal properties were not at risk of partial or total collapse for five to ten years? He accepted that was the position. Mr Turnbull accepted that the roofs of the appeal properties would be structurally stable for five to ten years even if no work was done to them. He said that was the position when he wrote his reports, and the only change was in respect of debonding. He accepted his position must be, therefore, that corrosion expansion was not going to result in the appeal properties becoming structurally unstable for five to ten years.
[106] On re-examination however he said the intention of the Act was to draw attention to a defect while it was still reportable and not likely to collapse imminently (unlike a dangerous building). He therefore again appeared to change his position and concluded that a building was structurally unstable if it had signs of recent or fresh movement, even though it might still be safe because the movement had not reached the degree that rendered the building unsafe.
[107] Although his position in respect of the structural instability of the roofs of the appeal properties due to corrosion expansion of the roof slab was confusing, he maintained the properties were structurally unstable due to the risk of the roofs collapsing as a result of debonding. He said;
“Structurally unstable, in the sense that there are signs of movement, and more recently finding that the steel is not bonded to the concrete; so there is a risk of structural failure.”
SUBMISSIONS
Pursuers’ Submissions
[108] The Pursuers’ counsel, Mr Fairley, submitted that the evidence of all of the experts who gave evidence on the issue (including the Respondent’s expert, Mr Turnbull), concluded that the properties to which these appeals relate are presently structurally stable and – even on the most pessimistic prognosis – will remain so for at least five to ten years without any maintenance works being carried out to them in the meantime.
[109] If that was accepted, it would be unnecessary for the Court to determine the cause of all or any of the cracks which had been noted as being present in the properties, or in the tenements of which the properties form part.
[110] Mr Fairley invited me, if I thought a determination was necessary however, to prefer the evidence of the Pursuers’ witnesses, Mr Morrison and Mr Balfour to that of the Respondent’s main witness, Mr Turnbull.
[111] Mr Fairley made the following submissions;
1 A house which is structurally unstable is necessarily unsafe simply because a structural element is at risk of collapse.
2 I should adopt a purposive approach to interpretation of the powers to serve demolition orders in terms of the 1987 Act, and that was one that took into account the safety considerations referred to in the Guidance.
3 Such an approach to interpretation must be conducted in a way as to recognise and give effect to Pursuers’ rights under art.1 of the First Protocol to the European Convention on Human Rights.
4 Mr Turnbull’s approach to interpretation of the Guidance was too narrow. Mr Turnbull said that spalling of concrete to an external part of the building was evidence of partial collapse. Mr Lindsay accepted that was a too narrow interpretation of ‘partial collapse’. Failure of a structural element of itself did not mean the building was structurally unstable. It was whether the result of the structural failure meant the building was at risk of partial or total collapse.
5 Mr Turnbull was selective in his interpretation of the Guidance, and he focussed on certain parts of the Guidance whilst completely ignoring others. Mr Turnbull wholly misunderstood the Guidance and, consequently, fell into error in his application of it to the concept of structural stability.
6 By looking only for evidence of recent movement, and in failing to consider whether or not such movement was evidence of a risk of partial or total collapse of the house, he misdirected himself. Mr Turnbull’s concession (from which he did not retreat even in re-examination) that, even on the most pessimistic scenario, the buildings would remain safe for between five and ten years was wholly destructive of any suggestion that they were presently structurally unstable on a proper construction of the Act and the Guidance.
7 Apart from his repeated assertions of structurally instability it was difficult, if not impossible, to understand what Mr Turnbull’s reasoning was by the time he concluded his evidence at the end of re-examination. In part, this may have been because of his attempts to adopt the mutually inconsistent positions of widespread corrosion expansion and widespread de-bonding at the same time.
8 Mr Turnbull carried out inadequate investigations and reached premature conclusions. He evolved a theory at a very early stage. He did so on incomplete information and then looked for evidence consistent with his theory. In so doing he either ignored or minimised the significance of evidence which tended to contradict that theory.
9 Mr Morrison was measured and careful in his approach. He did not rush to judgment, but considered all of the relevant evidence which was important to his decision before drawing a conclusion. His conclusion – that the theory of corrosion expansion was not supported by the evidence – could not be faulted. His explanations for the various cracks in the buildings were logical, supported by the totality of evidence, and should be accepted.
10 The court should have little difficulty in rejecting the evidence of Mr Turnbull to the extent that it conflicted with that of Mr Morrison (and Mr Balfour). Mr Turnbull’s approach was unscientific, speculative, selective in its treatment of the evidence and ultimately inherently inconsistent, careless, premature in reaching a concluded view on incomplete facts, and wholly lacking in the degree of care and objectivity required of an expert witness. What had at first appeared to be merely a difference of opinion between Mr Morrison and Mr Turnbull was in fact a manifestation of the very different way in which the two men approached their roles as experts.
11 On material areas of dispute the Court should have little difficulty in accepting the evidence of Mr Morrison’s more measured and scientific approach in preference to that of Mr Turnbull.
[112] I was invited to quash the demolition orders.
Defender’s Submissions
[113] Mr Lindsay made the following submissions;
1 There was no rational basis upon which the court could prefer one expert opinion over the other. Neither expert opinion was illogical or wholly unsupported by the primary evidence. As the court was faced with competing expert evidence it could not make any findings in fact relating to the structural stability of the buildings. As the onus of proof was upon the Pursuers, the absence of such findings in fact was fatal to their case in respect of the orders sought by the Pursuers’ first crave.
2 For a house to be structurally stable it must exhibit no signs of recent or fresh movement. Conversely, a house would be structurally unstable if it showed signs of recent or fresh movement. It was the presence or absence of signs of recent or fresh movement that was the essential definitional element of whether a house was structurally stable. It was submitted that the reference within the Guidance that a house may be at risk of either partial or total collapse was not a definitional requirement. It was simply an example of what the consequences of structural instability might be.
3 A house may be structurally unstable even if it was not at risk of partial or total collapse. All that was required for a house to be structurally unstable was for there to be signs of recent or fresh movement. Such an interpretation, he said, as well as being in accordance with the literal meaning of the Guidance was also consistent with the ordinary everyday meaning of structurally stable – which is that the structure is not moving.
DISCUSSION AND CONCLUSIONS
Discussion
Introduction
[114] There were numerous inspections and investigations of the various properties and a number of reports were prepared and lodged as productions. Many of the reports that were lodged did not find their way into the evidence before me. I should comment that some of the Defender’s evidence and reports, were quite graphic in their depiction of the various problems besetting the properties in the Clune Park estate, but they did not focus on the properties chosen jointly by the parties for this hearing. I did not allow general comments about the perceived problems evident with the estate to be attributed to the appeal properties where there was no evidential basis for so doing.
[115] The Defender’s position was based, in the main, on the evidence of David Turnbull, Civil and Structural Engineer, with ATK Partnership. Mr Turnbull inspected a number of properties in the Clune Park estate and, supported by the Stanger Testing Services Limited ferrous scanning and concrete investigation, and the verticality survey carried out by Pinnacle Phoenix Surveys (Scotland) Limited, he concluded that all the properties inspected had roofs that were structurally unstable and therefore were properties which fell below the tolerable standard. Mr Turnbull’s initial conclusion contained within his first report dated 14th March 2014, referred to a number of properties, three of which were appeal properties; 8 Clune Park Street; 8 Bruce Street; and 19 Robert Street. He concluded the cracking to internal and external walls was caused by the spreading of the flat concrete roof over the wall heads. That spreading was caused by lateral movement of the roof as a result of corrosion swelling of reinforced steel within the precast concrete slabs forming the roof deck. He explained that moisture penetrated the concrete, causing the steel reinforcement to corrode. That corrosion led to swelling of the steel and to cracks developing in the concrete. The cracks allowed water to penetrate the slab more easily and the process accelerated until, ultimately, the steel was no longer able to sustain the tensile forces and the units would in the future ultimately be liable to collapse.
[116] The Pursuers’ position, as set out by Mr William Morrison and Mr Ian Balfour, was that the properties were not structurally unstable. Mr Morrison accepted that there had been some movement in the roof slabs, but said the movement could not be attributed solely to corrosion expansion of the embedded steel within the concrete roof. His position was that there were a number of factors which might contribute to the expansion of the roof slab. Mr Balfour’s opinion was that there was little or no evidence of steel corrosion sufficient to cause the expansion of the concrete roof panels and the outward movement of external walls as a consequence.
Methodology
[117] The Balfour Engineering Consultancy Limited inspected the appeal properties. Mr Balfour was able to say which properties were subject to a disruptive survey, and how they were carried out. He was able to see the exposed steel within a number of the properties. As well as noting the presence of various signs, he also noted the absence of others. The Stanger Testing Services Limited’s inspection followed on from a further disruptive survey of 29th May 2014, and their report was dated 5th June 2014. The Balfour Engineering Consultancy Limited report was then issued after they had considered the Stanger Testing Services Limited report.
[118] William Morrison was instructed to carry out inspections of the appeal properties. He carried out non disruptive inspections of the properties and set out his detailed findings in respect of each of the individual appeal properties in his reports. His inspections included inspection of the roofs. He photographed the properties including the surface of the roofs.
[119] Mr Turnbull was first instructed by the Defender on 11th September 2013. He was initially instructed to inspect a number of the properties in the Clune Park estate and to provide a report on their condition. Mr Turnbull was unclear as to the extent of his instructions. He said he did not have a written brief from the Defender and that he was initially asked to carry out a walk-round survey and to give a report on the overall structural condition of the properties. Mr Turnbull was unclear as to whether or not he knew from the outset that the purpose of his report was to support a view that the properties may be below the tolerable standard.
[120] Mr Turnbull carried out an initial walk-round inspection of the affected properties. The detail of those surveys was not set out in his reports or in his evidence. Additional properties were then inspected by him, and a final group of properties was inspected on 18th March 2014. Access to the closes of that final group was not available, and so they were inspected from ground level. Significantly, Mr Turnbull’s report did not specify which properties were in that final group, and so when reading his report one has no idea in what manner and to what extent each property was inspected.
[121] Mr Turnbull accepted that by as early as December 2013, he had already reached a conclusion as to the cause of the cracks in the buildings, and that conclusion was that they were caused by corrosion swelling of the roof slabs. He accepted that he then looked for evidence to support his conclusion. Mr Turnbull’s conclusions were based on three site inspections in September 2013, and on photographs taken by the Defender. He accepted that he had never even been on the roofs to inspect the upper surface of the roofs. He accepted that he had not been inside any of the top floor flats. He said he had, however, been inside closes within the buildings. Mr Turnbull accepted, in evidence, that before reaching a conclusion about the cause of the cracking in the buildings he had not, in fact, entered any of the appeal properties.
[122] Mr Turnbull’s first report was prepared on the basis that it was believed the roofs were constructed from pre-cast concrete slabs, when the position was in fact that they were constructed from concrete poured in situ. The significance of the difference was explored in evidence, and whilst for reinforcement purposes that difference may not be much, it was worthy of note that the first report, which the Defender relied upon in deciding to issue demolition orders, proceeded on the basis of the wrong type of roof construction. It is of note that within the conclusions and recommendations section on page 5 of that first report, where access had been obtained to a vacant flat, it was reported that “it was clear that cracks were developing along the joints between adjacent pre-cast concrete units”. That clearly was incorrect, as there were no pre-cast units to create any joints. Mr Turnbull later said the cracks followed the line of the steel ribs. That did not sit well with Mr Turnbull’s position later on that the main problem of corrosion expansion was in the loops and not in fact the steel ribs. If that was the case, one might have expected the cracking to follow a different pattern, although Mr Turnbull did offer an explanation that where the wire looped down the side of the ribs that would create a similar directional force as the corroding ribs.
[123] Mr Turnbull’s report was based on a visual, non-disruptive inspection of the various properties. He estimated that the defect of corrosion swelling of the pre-cast concrete roof slabs affected more than 20 per cent of each roof. It is unclear how he could give such an estimate when he had not carried out a disruptive survey on any of the roofs, and had not been inside any of the top floor flats.
[124] Mr Turnbull prepared a second report, Production 10, revised in April 2015. By that time, he had the results of the Stanger Testing Services Limited report and he had the opportunity to see and comment upon the structural inspection report prepared by Balfour Engineering Consultancy Limited, dated 13th June 2014, and the report prepared by William Morrison dated 13th February 2015. He had not however carried out any further inspections and had still not been inside any of the appeal properties or been on the roofs. He subsequently gave evidence regarding the surface of the roofs without ever having seen them, and relied simply on photographs taken by others.
[125] As Mr Turnbull’s reports are littered with references to cracking of the walls being as a result of corrosion expansion of the roof structures (Mr Balfour noted Mr Turnbull’s first report attributed twenty five structural defects to the corrosion of steel reinforcement and the horizontal movement of the slab), I find it surprising that he could reach his conclusions, and also maintain them in his second report, without ever having been inside any of the properties, or having been on the roofs.
[126] I have some difficulty with the methodology adopted by Mr Turnbull. Mr Turnbull was instructed by the Defender as an expert to provide an opinion. He was unsure of his initial remit, and could not recollect in evidence at what stage he became aware that his opinion might be used to support a decision to serve demolition orders. He accepted that early on he came to a conclusion as to the reasons for the cracks in the buildings, and he looked for evidence to support his conclusion. I believe his approach was flawed. It was based on an inadequate inspection of the properties and an initial erroneous conclusion as to the roof structure, and of the extent and pattern of the reinforcement steel. Even with those limitations, he was prepared to give estimate percentages for the existence of the effects of corrosion expansion within the roofs across the whole estate. He appeared to close his mind to other possible causes of cracking, and did not address them in his reports. He failed to take account of, and comment on, the absence of indicators, such as corrosion staining or spalling, that should perhaps have been present if his conclusion was correct. I agree with Mr Fairley, that Mr Turnbull’s evidence was not what might be expected of an expert witness. It was unscientific, speculative and selective in its treatment of the evidence. It was ultimately inherently inconsistent and confusing.
[127] By contrast, I found both Mr Balfour and Mr Morrison carried out detailed inspections of the appeal properties before they gave their expert opinions. At the meeting for the Scott Schedule, Mr Turnbull rarely agreed with the views of Mr Morrison or Mr Balfour. At that stage Mr Turnbull was insisting the various defects were caused mainly by corrosion expansion of the steel ribs. That of course was a position he then departed from. When Mr Turnbull thought of his theory of debonding, it was approximately six months after he had inspected the properties. I would have thought that such a drastic change from an earlier position he had steadfastly maintained would have merited a further inspection of the properties. I did not have confidence in Mr Turnbull’s opinion on matters. Where there was a conflict of opinion between Mr Turnbull and Mr Balfour or Mr Morrison, I generally favoured the more thoughtful opinion of Mr Balfour or Mr Morrison to that of Mr Turnbull.
[128] After Mr Turnbull’s first report, on the instructions of the Defender, an inspection of the roof was carried out by Stanger Testing Services Limited. The report from them concluded by saying that the break-outs which had been created in the concrete exposed steel joists showed signs of significant surface corrosion. Several of the 6 mm O-bars were found to be fully corroded and crumbled and broke off from the concrete. Significantly, however, the break-outs carried out by Stanger Testing Services Limited were not in any of the properties which are the subject of these appeals.
[129] By the time the demolition orders were served in June 2014, the Defender was therefore relying upon Mr Turnbull’s report, together with the Stanger Testing Services Limited’ report. It was clearly a significant step for the Defender to serve demolition orders on approximately 300 properties, and those orders had potentially significant consequences for each individual proprietor. It was, therefore, somewhat surprising that in deciding in each and every case to serve a demolition order, the Defender relied on, (a) a structural engineer’s report that was clearly based on inadequate inspections and which contained extrapolated assumptions based on those inspections, and (b) a technical report which found varying levels of corrosion in the properties inspected. It seems a very broad brush approach indeed was taken to the serving of the demolition orders.
Corrosion expansion
[130] Mr Turnbull’s principal conclusion, and no doubt a significant factor in the Defender’s decision to serve the demolition orders, was that corrosion expansion of the steel ribs was the cause of the movement of the roof. That was a conclusion he subsequently departed from.
[131] Mr Turnbull originally thought the roof was constructed using pre-cast concrete panels. His second report acknowledged that the roofs were poured in situ concrete, but he gave a very similar explanation for the pattern of cracking, notwithstanding that in evidence he said the steel reinforcement in the two types of concrete roof was quite different.
[132] In that first report, it seemed to me that Mr Turnbull raised two issues. Firstly, there was corrosion expansion of the steel within the roof slabs leading to movement of the roof slabs, and that was evidenced by cracking appearing in the ceilings and in the gable walls and elevations. The second was that as the concrete cracked, and more water penetrated, the process accelerated until the steel was no longer able to sustain the tensile forces, and the units, i.e. the roof slab, would ultimately be at risk of collapse. I do not believe the second issue was truly recognised at that stage, either by Mr Turnbull or by the other experts, or if it was, it seems never to have been considered as a significant problem (if indeed it is).
[133] Mr Turnbull’s theory of extensive corrosion expansion to explain the external cracks to gables and elevations was based on cracking running along the lines of the corroding steel ribs. According to him all the evidence pointed to cracking running along the lines of the steel ribs and not in the direction of the secondary steel. He gave calculations based on the number of ribs and by how much each rib might expand to explain the evidence of gable cracking, wall head rotation and a tearing of the elevations away from the internal supporting walls.
[134] Mr Morrison did not agree with Mr Turnbull’s interpretation of the cracking evidence, and did not agree that the roof slabs were moving because of corrosion and swelling.
[135] Mr Turnbull’s conclusions as set out in his reports seemed to be his position heading towards the hearing. The Defender however adjusted late in the day, and their pleadings became confusing and ultimately inconsistent with the evidence led on this point.
[136] The Pursuers’ position on record was;
“The roofs have been constructed using a poured, in situ concrete slab formed between ribbed steel plates at 500mm centres. No other steel reinforcement rods or bars exist within the roof slabs.”
[137] The Pursuers maintained that position, notwithstanding the terms of the Stanger Testing Services Limited report which identified 6mm O bars at 400mm – 600mm spacing lying perpendicular underneath the ribbed plates. It was stated by Mr Fairley that the Stanger Testing Services Limited report did not in fact deal with any of the appeal properties, but Mr Fairley did not object to evidence within the report being led in evidence. Stanger Testing Services Limited’s remit was to carry out a survey of the roof slab construction within the Clune Park Estate. The various properties inspected, including Flat 3/1 Clune Park Street (which was the top floor flat next to the appeal property Flat 3/2), all had the same roof construction and, it would be reasonable to assume, unless there was evidence to the contrary, that the construction of the roof slabs was consistent throughout the estate. When Mr Morrison was questioned on what he understood the steel reinforcement structure to be, he said he saw the main steel ribs, but did not see any thick rods running at right angles to them. He had seen some tying wire, which he said was about 1 ½ to 2mm at most.
[138] The Defender’s position on record (in answer 5.4, headed, ‘Roof Structure’) was;
“The slab was reinforced by steel ribs measuring 7mm x 75mm, spaced 600mm apart, which span the width of each room. These ribs were placed on top of circular distribution bars, which measured 6mm in diameter. The circular bars were spaced at approximately 400mm centres. The bars spanned the length of each room……..”
[139] The Pursuers refer in their pleadings to the reinforced steel as ‘steel bars’ or ‘ribbed steel plates’. The Defender refers to these main elements as ‘steel ribs’ The Stanger Testing Services Limited report refers to them as ‘reinforcement joists’. I have referred to them throughout this judgment as steel ribs. The Defender went on to describe the 6mm diameter steel lying underneath and perpendicular to the ‘steel ribs’, as ‘circular distribution bars’ or ‘circular bars’ which measured 6mm in diameter and were spaced at approximately 400mm centres. The Defender is clearly describing what is referred to as the 6mm O bars detailed in the Stanger Testing Services Limited report and reported by them as lying underneath and perpendicular to the ‘steel ribs’.
[140] In condescendence 5 the Pursuers refer to Mr Turnbull’s reports. The Pursuers clearly address the issue of the pattern of the steel reinforcement within the roof. They address corrosion of the embedded steel and the effect of any expansion of the roof slab on the front and rear elevations of the buildings, and the issue of cracking and its causes.
[141] The Defender’s pleadings were in the following terms;
“The 75mm by 6mm steel bar used in the concrete roof slabs does not provide direct support to the concrete and relies on the 6mm loops of mild steel wire to prevent the concrete dropping between adjacent steel bars. These steel bars are now seriously corroded and the risk of concrete falling increases year by year. Further, the steel is no longer bonded to the concrete. The composite action between steel and concrete is therefore lost, and the roof in its present condition relies only on the capacity of the 75mm x 6mm steel beam. These beams are not capable of supporting the dead load of mastic asphalt concrete slab and ceiling finishes over the width of a typical room within the Estate.”
[142] The Defender said the steel ribs spanned the width of each room, and the circular distribution bars the length of each room. The Defender however had apparently introduced a third steel component, ‘steel wire loops’. They had also introduced a new mechanism, which appeared to support their debonding theory, but which was never indicated in the pleadings as being such.
[143] In answer 5.5, headed, ‘Inspection’, the Defender detailed the results of various inspections and returned to the issue of cracking caused by corrosion expansion. In noting the cracking they stated;
“These indicate that the reinforcement bars are substantially corroded and have disintegrated completely in places. The steel ribs were also noted to have corroded. The cause of the said internal and external features is the swelling of the steel ribs imbedded in the roof slab.” (my emphasis).
[144] The Defender then stated at answer 5.6, headed, ‘Common Defect’;
“Eventually, the steel ribs will be no longer able to sustain the tensile forces, resulting in failure. The buildings comprising the Estate are not structurally stable for the purposes of the tolerable standard. If no work is undertaken in respect of the roofs throughout the Estate leaks will become established, accelerating the corrosion of the main bars and secondary bars within the roof slabs”.
There was no mention of steel loops.
[145] The difficulty with the Defender’s pleadings is that although in Answer 5 they do helpfully set out the main issues to be addressed in headed paragraphs, the Defender did not answer the points raised by the Pursuers, and importantly did not use the same terminology when referring to the reinforcement steel. This led to confusion on the part of the parties at the hearing as to what the Defender’s position was regarding the pattern and structure of the reinforcement steel within the concrete.
[146] It was unfortunate the confusion in terminology and in the pattern and components of the steel reinforcement were not addressed prior to the hearing. It led to confusion on the part of the Defender on record and confusion on the part of the parties during the evidence as to what Mr Turnbull’s position was as to the main cause of the corrosion expansion, and further, whether it was corrosion expansion or debonding that was the major risk to the roofs.
[147] Not only did the Defender introduce the reference to “6mm loops of mild steel”, they also appear in their pleadings to have largely ignored the effects of corrosion expansion, and concentrated on the risk of concrete falling between the corroding steel.
[148] The Defender’s position heading towards the hearing, although far from clearly stated in the pleadings, was that corrosion of the steel ribs was the main cause of the corrosion expansion of the roof slab, and that was the main feature in declaring the buildings to be structurally unstable. When giving evidence however Mr Turnbull departed from that. He referred to the steel loops, and on the issue of corrosion expansion said, “I see corrosion of the loops as the greater defect”. Of the steel loops he also said, the ‘happy side effect’ of them was that they provided additional reinforcement, preventing the concrete dropping between the steel ribs. This ‘happy side effect’ seems to have taken on greater significance, as according to Mr Turnbull, the corrosion of the steel loops and the resultant failure of the ‘happy side effect’ would, result in the roofs collapsing internally.
[149] That was quite a departure from his previous theory of corrosion expansion of the steel ribs being the main concern, and Mr Turnbull did not support the Defender’s case on record. The issue of movement of the roof caused by corrosion of the steel loops was never put to the Pursuers’ witnesses, presumably because corrosion of the steel loops had never been mentioned in the pleadings and the Pursuers’ representative, and perhaps also the Defender’s, were not aware of that as an issue.
[150] All of this simply left me further confused as to the basis of Mr Turnbull’s conclusions in his reports as to the cause of the cracking to the ceilings, and its effect on the gables and on the front and rear elevations. Mr Turnbull’s reports and his calculations were framed on the basis that cracking of the ceilings (which was a sign of corrosion expansion of the steel) was following the lines of a number of parallel steel ribs, and was causing the elevations to be pushed out. There was no indication in the pleadings that corrosion of the steel loops had anything to do with cracking caused by corrosion expansion.
[151] Mr Fairley rightly objected to detailed evidence being led on the existence and effect of corrosion expansion of the steel loops, as it had not been properly pled, and had not been put to the Pursuers’ witnesses. Mr Morrison had been asked about what he had seen when the ceilings were opened and he spoke of seeing steel wire which he thought was 1mm-2mm thick, and not 6mm as stated in the Stanger Testing Services Limited report. He said it might have been used to hold the ribs in place during the pouring of the concrete, but he was not asked if it had any reinforcement purpose.
[152] Mr Lindsay agreed not to pursue the line that corrosion of the loops was relevant for the expansion case being put forward. Mr Lindsay accepted that his corrosion expansion case relied simply on the corrosion of the steel ribs as set out in the reports and in the pleadings. He said that corrosion of the steel loops would be relevant however to the issue of the roof falling in on itself due to the lateral support corroding.
[153] The Defender ultimately therefore was constrained to relying upon corrosion of the steel ribs to support the theory of a moving concrete roof slab, and on corrosion of the steel loops to support the theory of debonding and the falling/collapsing roof slab. Unfortunately the evidence of Mr Turnbull in relation to corrosion expansion did not support the Defender’s case on record.
[154] In support of the Pursuers’ position in relation to corrosion expansion of the roof slab, Mr Morrison said that he would expect to see as evidence of corrosion expansion, rust staining on the underside surface of the roof running along the lines of the steel that was corroding. Where the steel ribs expanded due to corrosion, he would expect to see the plasterwork underneath spalling. He would also expect to see linear cracking running along the lines of the steel ribs. Mr Morrison‘s evidence was that he saw little or no evidence of rust staining, linear cracking or spalling along the lines of the steel ribs in the properties subject to the appeals.
[155] In view of the Defender’s corrosion expansion case being restricted to the steel ribs and not the steel loops, Mr Turnbull was not able to explain adequately in evidence why, if the main corrosion expansion was in the steel loops which ran perpendicular to the ribs, as he ultimately maintained, the cracking was not following the lines of the steel loops. He did seek to suggest that corrosion to the wire running down the sides of the ribs would have a similar effect to corrosion of the ribs themselves, but in view of the position agreed by Mr Lindsay not to explore corrosion expansion of the loops any further, this was correctly not pursued.
[156] The difficulty for the Defender in trying to insist that corrosion of the steel ribs was the main issue affecting the roofs was firstly, there was little evidence of anything other than surface corrosion of the steel ribs, and secondly, that Mr Turnbull said it was not the main issue. When Mr Turnbull was asked if the cumulative effect of the surface corrosion of the twenty steel ribs within the roof slab would generate enough expansive force that the roof slab would move out, he said “Not for the plates themselves”…. “Having seen this flat the corrosion of the loops was the defect I would say is responsible”.
[157] He also said;
“We first of all have taken it that corrosion of these steel plates led to the expansion, and that is how the report was drafted and that is how the report was phrased”, … and …. “Yes. It shows that if the corrosion of the main ribs is not the principal cause then the secondary loops must be the cause.”
[158] Mr Turnbull was simply not clear as to the pattern and structure of the steel reinforcement within the concrete roof. That is perhaps understandable as the scans contained within the Stanger Testing Services Limited report were not particularly clear. The difficulty however with Mr Turnbull’s evidence is that he clearly nailed his colours to the mast early on by stating that the cracking in the ceilings was following the line of the steel ribs, and that it was the steel ribs that were corroding. He went as far as saying in his first report that, “the defect (corrosion expansion of the concrete roof slabs) affects more than 20% of each roof.” I do not see how he could arrive at such a conclusion, having never examined the inside of the properties. In my view such comments seriously undermine Mr Turnbull’s evidence.
Debonding
[159] Mr Turnbull began his evidence by saying he had considerable experience of working with tenemented property, and dealing with reinforced concrete, and had come across many concrete floors that had become corroded through time. With that background, I would have thought Mr Turnbull would be very familiar with the principle of debonding of steel and concrete. His final position in relation to the appeal properties seemed to be that the various roofs were at risk of collapsing in on themselves due to both corrosion of the steel wire and debonding of the concrete from the steel. Considering his experience of concrete I was left wondering why debonding had not been considered by Mr Turnbull at the outset. It may be the answer lies in Mr Turnbull deciding early on that corrosion expansion was the cause of the roof movement, and that he simply looked for evidence to support that. By concentrating on corrosion expansion, Mr Turnbull was perhaps in danger of ignoring other evidence pointing to other possible causes of the roof movement. That might explain why, if there was evidence at the initial site investigations or at the meeting for the Scott Schedule, of the steel and the concrete becoming debonded, it was not instantly recognised by Mr Turnbull, and investigated by him as a possible explanation of the various findings.
[160] By the date of the final revisal to his first report, dated 14th March 2014, Mr Turnbull had not examined the properties, but had sight of photographs taken by Inverclyde Council. He accepted that he had been looking for information consistent with his original theory of corrosion swelling. He said he had not heard a more convincing theory as to the cause of the cracking.
[161] Mr Turnbull had not referred to debonding in either of his reports. He accepted there was also no mention in any of the reports of deflection of the inside faces of the roofs. When considering deflection of the external surface of the roof slab, debonding as a possible cause had not occurred to him. He explained that the issue of debonding only occurred to him in December 2015. The Scott Schedule, which had been produced in December 2015, following upon the July 2015 inspections which Mr Turnbull had attended, made references to gaps between the concrete and the steel. Although gaps between the concrete and steel were mentioned, the implications were not stated.
[162] The evidence for debonding seemed to me to be scant. Mr Turnbull arrived at his conclusion that there was debonding some six months after his last (and it seems only) inspection of the properties. One would have thought that with such a major change of opinion as to the main reason to support a finding of structural instability, Mr Turnbull might have carried out a further inspection to confirm his view. He did not, and his opinion that there was extensive debonding throughout the Clune Park estate was therefore reached on the basis of an examination some five months earlier, of two very small areas at one location that had been exposed. Those areas had been examined to look for corrosion in the steel, and therefore the significance of any gaps in the steel may not have been appreciated at that time (and obviously wasn’t), and therefore their exact dimensions would not have been appreciated, or noted with any precision at that stage. The photographs submitted did not greatly assist at the hearing. No particular thought seems to have been given as to how the steel was exposed for examination, and if the method of exposure could have created cracks or gaps between the steel and the concrete. Mr Turnbull was not there when the rib was exposed, and from his evidence it is difficult to see how he could say the concrete was not bonded to the steel prior to it being chiselled out.
[163] Mr Turnbull’s theory of debonding was not intimated to the Pursuers. Mr Turnbull explained the reason for the lack of notice of his change of position by saying the issue of debonding only came to him on waking on Christmas Eve in 2015, a matter of four weeks or so before the hearing. This new issue of debonding had been adjusted into the pleadings very late in the day and, given the Defender’s confusion with the terminology for the different elements of steel within the roof, Mr Turnbull’s debonding theory was not clearly expressed in the pleadings.
[164] I have grave concerns that a very limited inspection of two very small areas is being advanced by the Defender to support a general proposition of debonding in respect of all of the appeal properties. I simply do not accept there is the evidence available from that very limited inspection to arrive at such a conclusion of widespread debonding in the appeal properties.
Deflection
[165] Mr Morrison said that ponding of water was not necessarily a sign the roof was sagging. It could be caused by different thickness of screed being laid on the surface to create a run off. Where there were signs of deflection, he saw them in areas where he would not expect to see them, such as in the corners of the buildings. He would expect to see deflection in the middle of rooms where the roof was not supported by internal walls. Mr Morrison said there was no excessive deflection of the roof slab which indicated severe corrosion of the embedded steel in the roof slab.
[166] Mr Turnbull said the deflection was evidence of debonding, and of the roof sagging under its own weight. In his second report, Mr Turnbull recognised that Mr Morrison raised the issue of deflection in his report, but Mr Turnbull appeared to ignore deflection in his. He did not use deflection to support his theory of extensive corrosion expansion, but did use it later to support his theory of debonding.
[167] I am of the view that Mr Morrison was more thoughtful and measured in considering any deflection of the roof, its causes and its effects, whereas, Mr Turnbull ignored it when it didn’t fit with his theory of corrosion expansion and relied upon it when it fitted with his theory of debonding.
Structural Stability
[168] A house meets the tolerable standard for the purposes of the Housing (Scotland) Act 1987 if the house is structurally stable. In construing any such reference to the tolerable standard, regard shall be had to the Guidance issued by the Scottish Ministers in 2009, “Implementing the Housing (Scotland) Act 2006, Parts 1 and 2. Advisory and Statutory Guidance for local Authorities”. “Volume 4 Tolerable Standard” provides guidance on inter alia, the definition of houses not meeting the tolerable standard, the definition of tolerable standard and the definition of structural stability.
[169] Parties were unable to agree what was meant by ‘structurally stable’, and I was not referred to any material other than the Guidance to assist me in understanding it.
[170] The Pursuers’ position, by reference to Chapter 4.7 of the Guidance, was,
“The structural elements of a house should exhibit no signs of recent or fresh movement...”,
and therefore one must look at the structural elements, e.g. the roof, and further, one must look for signs of recent or fresh movement of that structural element.
[171] What then needs to be considered is whether or not those signs of recent movement in a structural element constitute evidence,
“….which may indicate to the assessor that the house may be at risk from either partial or total collapse.”
That is, might any evidence of recent or fresh cracks indicate that the house may be at risk of partial or total collapse, rather than simply a structural element of the house?
[172] The Defender’s position was that for a house to be structurally stable it must exhibit no signs of recent or fresh movement. Conversely, a house will be structurally unstable if it shows signs of recent or fresh movement.
[173] According to Mr Lindsay, it is the presence or absence of signs of recent or fresh movement that is the essential definitional element of whether a house is structurally stable. It was submitted that the reference within the Guidance, that a house may be at risk of either partial or total collapse, was not a definitional requirement. It was simply an example of what the consequences of structural instability may be.
[174] Mr Lindsay said that if the risk of collapse was part of the definition of structurally stability, then the Guidance would be in the following terms [differences highlighted];
“The structural elements of a house should exhibit no signs of recent or fresh movement, evidence of which may indicate to the assessor that the house may be is at risk from either partial or total collapse.”
[175] He submitted that as the Guidance was not in those terms it was clear that the risk of collapse is not a definitional requirement. That meant, according to Mr Lindsay, that a house may be structurally unstable even if it is not at risk of partial or total collapse. All that is required for a house to be structurally unstable is for there to be signs of recent or fresh movement. Such an interpretation, he said, as well as being in accordance with the literal meaning of the Guidance is also consistent with the ordinary everyday meaning of structurally stable – which is that the structure is not moving.
[176] It was submitted there was nothing surprising or illogical about the definition of structurally stable not including the risk of collapse as an essential requirement. The provisions of the 1987 Act relating to demolition orders required to be considered in the context of the wider statutory powers possessed by local authorities relating to defective and dangerous buildings. Many of those powers can be used to deal with buildings which are at risk of collapse.
[177] Mr Lindsay said the Guidance was only guidance and I was not bound by its definition of structural stability. That is true, but the Guidance does have some authority, and I am obliged to give consideration to it.
[178] Although he was supported by Mr Turnbull, I do not agree with Mr Lindsay’s interpretation of the Guidance in this regard, and I agree with the interpretation given by Mr Fairley, as supported by Mr Morrison.
[179] Mr Morrison said the structural elements of a building are those parts which carry and distribute load in addition to their own self-weight and include the foundations, walls, roofs, floors and stairs. Stability is the resistance of a structure to sliding, buckling, excessive deflection or overturning. The structure of a building is fundamental to ensure the safety of its users and of the general public. Mr Morrison stated that there were a number of definitions of the term “structural stability” but they all generally had the same meaning. The Guidance stated that an assessor, in considering structural stability, should look for reasonable signs of potential instability in any structural element of the building, as a house if structurally unstable would normally show signs that it is moving, or that a structural element is likely to fail.
[180] I do not accept the Defender’s submission that it is simply the presence of recent movement of the structural elements of a building that renders a building structurally unstable, and I prefer the Pursuers’ interpretation of Chapter 4.7. It is necessary that consideration be given to the possible consequences of the recent movement, e.g., might there be a risk of partial or total collapse?
[181] What requires to be considered when looking at the structural stability of a house are the structural elements, and that clearly includes the roof, gables and elevations. Those structural elements (the roof in this case) should not exhibit signs of fresh movement which may indicate a risk of partial or total collapse. That does not mean that every movement of a structural element renders a building structurally unstable. Buildings, and that includes their structural elements, are designed to move. It is only where the movement might indicate there is a risk of partial or total collapse that there is an issue. So, in considering structural stability, it is only when the structural elements exhibit certain signs of movement, i.e. ones that may indicate partial or total collapse, that there is an issue.
[182] But collapse of what? In referring to the Guidance and to his report, Mr Morrison said it was the house that must be at risk of partial or total collapse. Individual structural parts of the building may show signs of partial or total collapse but, in his opinion, that did not render the building as a whole structurally unstable.
[183] Mr Lindsay submitted it was only the “main structural elements of a house” that were required to be at risk of partial or total collapse, and not the house itself. The main structural elements of a house are listed in Chapter 4.7. That meant, according to Mr Lindsay, that the collapse of a roof structure or of a floor would be a partial collapse for the purposes of Chapter 4.7. The link between the reference to “partial collapse” and the listing of the main structural elements was clearly established by their close proximity in the Guidance and, in any event such an interpretation accords with the ordinary everyday meaning of partial collapse. Mr Turnbull’s interpretation of the Guidance was also that it was partial or total collapse of the structural element.
[184] But that is not what the Guidance says. The Guidance says, “that the house may be at risk from either partial or total collapse.” To follow the Defender’s reasoning would mean that if part of a roof, e.g. the overhang, was at risk of falling that would render the property below tolerable standard. Mr Turnbull said that was his understanding of the Guidance, but Mr Lindsay was not prepared to go as far as that, and he was not prepared to say that if part of an overhang of a roof fell down, that would render the building below tolerable standard.
[185] Chapter 4.10 of the Guidance provides (with my emphasis):
“4.10. When assessing a house against this element of the tolerable standard, an assessor should look for visible signs of potential instability in any structural element of the building. This will allow him / her to consider the stability of the building as a whole.”, and to Chapter 4.14 which provides:
“4.14. The tables show indicators of potential instability and do not necessarily mean on their own that a structural element, or the house as a whole, is structurally unstable.”
[186] Chapter 4.14 differentiates between the structural stability of a structural element, and the structural stability of the house as a whole. Chapter 4.7 defines ‘structurally stable’, and that definition is with reference to the house, and not the structural elements, being at risk of partial or total collapse. Further, the definition of ‘structurally stable’ in Chapter 4.7 is with reference to Chapter 4.1, which states that ‘a house’ meets the tolerable standard if it is structurally stable.
[187] It is by considering the evidence of potential instability in the structural elements of a building, that the stability of a building as a whole is assessed. A house of course comprises many elements, and the roof, gables and elevations are significant examples of those. If a roof partially or totally collapses, then in certain situations that might be to such an extent that it could be said the building has partially or totally collapsed. If an elevation or a gable was to partially collapse that could very well mean that the building has partially collapsed. In my view (supported it would seem by Mr Lindsay), spalling of a piece of masonry from an elevation would not however be considered to be a partial collapse.
[188] I turn to the evidence regarding structural stability in relation to the appeal properties. Mr Turnbull was of the opinion that the buildings showed signs of fresh movement. He said;
“In my view the roof structures and other roof features are at risk from either partial or total collapse. The degree of movement in the external walls would not suggest complete collapse of the wall, but localised spalling of concrete or masonry, as has now happened will manifest itself. This spalling or falling of masonry and concrete is the partial collapse of one of the structural elements, being the roof.”
[189] It seems to me that Mr Turnbull at this point was referring to external parts of the roof structure falling to the ground.
[190] Mr Turnbull referred to Chapter 4.21 to support his proposition that the roof spreading across the wall heads would lead to collapse of the roof;
“Spreading roof structures with the outer ends of the roof moving apart and the roof height dropping (accompanied by bulging of the upper walls)”.
[191] I do not interpret the Guidance on this point in that way. Chapter 4.21 states that if there is evidence of movement, an assessor needs to decide if this means the house is at risk of being structurally unstable. My reading of the Guidance is that if there is evidence of a roof spreading and dropping, that may be evidence of a structurally unstable roof, which may in due course collapse. Mr Turnbull did not refer in his report to any evidence of the roof height dropping (in evidence he did mention deflection of the roof). His only mention of the roof dropping was at the point of collapse of the roof. Obviously if a roof collapses it will drop in height. I would have thought the mechanism (of spreading and dropping of height) could more properly be attributed to pitched roofs if they are not cross supported properly, which thereby results in the rafters in the roof trusses spreading out where they meet the wall heads, and by spreading out, dropping the height of the ridge.
[192] Mr Turnbull then went on to say in Paragraph 11 of his second affidavit, that the steel was no longer bonded to the concrete, and that calculations attached to his affidavit had shown that the beams were not capable of supporting the dead load of concrete and ceiling finishes over the width of a typical room. He concluded that on that basis the roof was at risk of partial or total collapse. He gave an example of a severe snow fall possibly prompting excessive deflection of the roof and ultimate failure of the roof slab.
[193] Mr Turnbull is clearly pursuing two quite distinct possible failures of the roof. Firstly, he is saying that the roof is spreading and that is leading to cracking of the walls at the wall heads. The overhang of the roof slab is cracking and is precarious. I do not believe he is saying the walls are liable to collapse, and certainly there was no evidence of that. These features raise the possibility of falling masonry or concrete. He concluded: that is evidence of partial or total collapse of the building and thus the building is structurally unstable. For the reasons given above, I do not accept that to be the case.
[194] Mr Turnbull does not seem to have considered the stability of the building as a whole. He has not only limited himself to one component of the building, the roof (which indeed is an extremely important one), but has limited himself further by considering the risk of partial collapse of perhaps only a small element of that component (e.g. the overhang). I do not believe Mr Turnbull has done what the Guidance says should be done, and that is, to consider the building as a whole, and consider if the building is at risk of partial or total collapse.
[195] Secondly, he is saying that corrosion of the steel loops is such that the roof slab is at risk of collapsing in on itself. Clearly that is a serious matter, and if that was the case then the house may be at risk of partial collapse, and therefore below tolerable standard. For the reasons given above, I am not satisfied there is sufficient evidence from the very limited inspection of two small areas of steel for Mr Turnbull to arrive at that conclusion.
[196] Even if I was to accept Mr Turnbull’s interpretation of the Guidance, that would still leave the Defender with some difficulties. Although Mr Turnbull said the appeal buildings were currently moving as a result of the roofs spreading, he said however:
“I am not saying the structural element is currently failing, but I do say it is moving. The corrosion of the bars within the roof is a progressive and irreversible defect. As it corrodes the roof will accordingly keep moving. It is my view this manifestation will lead to structural failure within the next five to ten years and accordingly the buildings will certainly be classified as dangerous or ‘unsafe’”
[197] He said the buildings were moving but were currently safe, and would remain so for five to ten years. In his second affidavit, Mr Turnbull referred to the Guidance in some detail. He noted and agreed with Chapter 4.2, which stated that; “Instability in the structure of a house is an obvious threat to the occupants’ safety”. Chapter 4.2 of Volume 4 of the Guidance established a clear link between the concept of structural stability and that of occupant safety.
[198] The particular risk to occupant safety which is identified as arising from structural instability is that of “either partial or total collapse” of the house. A house which is structurally unstable is necessarily unsafe simply because a structural element is at risk of collapse. It did not follow, however, that a house which was unsafe was necessarily also structurally unstable. Safety considerations may arise from a variety of other factors short of partial or total collapse of a structural element. I was invited by the Pursuers to consider Chapter 4.7 as a whole. An assessor, when looking at a building should look for evidence of recent or fresh movement in a structural element of a building that might indicate to him that the house, as a whole, may be at risk of partial or total collapse. Mr Fairley submitted that the purpose of the legislation was to see if there was a risk of the house as a whole being subject to partial or total collapse.
[199] It was possible, according to Mr Turnbull, to have a structurally unstable building in terms of the Guidance that was not presently dangerous, but may later become dangerous. Mr Turnbull’s proposition proceeded on the basis that the roofs would continue to leak if there was no work done to them.
[200] The buildings have to be assessed in their current condition however, and it has never been suggested that they would not be subject to routine maintenance. It appears from the photographs and reports on the roofs that the roofs have had routine maintenance carried out to them.
[201] Mr Morrison suggested that ‘imminent’ risk of either partial or total collapse, might mean within six months to one year. He said if a building was considered safe for the next five to ten years, he would consider it to be structurally stable. If the building was structurally unstable then it must be considered unsafe, but an unsafe building, however, was not necessarily a structurally unstable building.
[202] The Pursuers suggested I adopt a purposive approach to interpretation of the powers to serve demolition orders in terms of the 1987Act, and that was one that took into account the safety considerations referred to in the Guidance.
[203] The Pursuers submitted that such an approach to interpretation must be conducted in such a way as to recognise and give effect to Pursuers’ rights under art.1 of the First Protocol to the European Convention on Human Rights – “Protection of Property”.
[204] Whilst art. 1 of the First Protocol permits a level or degree of state interference with individual property rights, a “fair balance” requires to be struck between the demands of the general interest of the community on the one hand and the requirements of the protection of the individual’s fundamental property rights on the other.
[205] In the present context, any interpretation of the 1987 Act which permitted the exercise of the power to serve a demolition order in relation to a building which – even without maintenance – would remain safe and structurally stable for at least five years, (and possibly longer) would not represent the “fair balance” envisaged by art 1.
[206] I agree with Mr Fairley when he says that the appropriate interpretation of Section 115 of the 1987 Act is that it permits service of such an order on a building which is either (a) presently structurally unstable; or (b) at imminent risk of becoming so. Such a purposive interpretation is consistent both with the Guidance and with the Pursuers’ rights under art. 1 of the First Protocol.
[207] On the crucial issue of structural stability, the Defender is in some difficulty. Mr Turnbull accepted a building could not be considered safe if it was at risk of partial or total collapse. He stated the appeal properties’ buildings would be safe for five to ten years. The inevitable conclusion that was put to him was that those buildings must therefore not be at risk of partial or total collapse for five to ten years. He accepted that was the position. Mr Turnbull accepted that the roofs of the appeal properties would be structurally stable for five to ten years even if no work was done to them. He said that was the position when he wrote his reports, and the only change was in respect of debonding. He accepted his position must be, therefore, that corrosion expansion was not going to result in the appeal properties becoming structurally unstable for five to ten years. In his affidavit dated 17th December 2015, he said; “I am not saying the structural element is currently failing, but I do say it is moving. The corrosion of the bars within the roof is a progressive and irreversible defect. As it corrodes the roof will accordingly keep moving. It is my view this manifestation will lead to structural failure within the next 5 – 10 years and accordingly the buildings will certainly be classified as dangerous or unsafe.” It was difficult to reconcile Mr Turnbull’s position on this issue with his assertions that the buildings were structurally unstable by reason of corrosion expansion.
Movement of the building
[208] This case is about structural stability, and as is clear from the preceding paragraphs, at the heart of that is the movement of a building. The crux of this case is whether or not the buildings are moving and therefore liable to collapse.
[209] The Defender instructed a series of verticality surveys on various properties. The first surveys were carried out in October 2014, the last in May 2015, and they showed that the buildings were out of plumb to various degrees. All of those surveys involved taking a single measurement on a particular day. Mr Hunter was not instructed to monitor the buildings for movement, an exercise he had done many times for other buildings suspected of moving.
[210] Mr Morrison said in evidence he saw no tangible evidence that the buildings were continuing to move. He saw no evidence of crack monitoring having taken place. He noted that some cracks had been repaired and had re-opened. In his view this was due to inappropriate filler having been used to repair the original cracks. The fact that the cracks had opened again did not provide sufficient evidence that there was progressive movement in the building. His opinion from looking at the cracking, and using his experience, was that the cracking appeared of some age.
[211] Mr Turnbull was of the opinion the buildings were moving. He pointed to the verticality study and the reopening of the filled cracks. He thought the cracks appeared recent.
[212] There are a number of matters worthy of comment. Chapter 4.11 provides:
“We explained in chapter three that housing staff and other professionals assess houses against the tolerable standard for two distinct purposes: local / national house condition survey work; and possible enforcement action. This difference is particularly important for structural stability as it influences the factors an assessor will be able to consider:”
“….Where an assessor is examining a house as part of a house condition survey, he/she will need to base his/her judgment on a one-off walk-through survey. Assessors may be able to form a clear opinion during a single visit in some cases. But there are inevitably limitations because the assessor cannot track the building over time.”
“Where a local authority is examining whether an individual house is structurally stable for the purpose of possible enforcement action, it is able to monitor the house over time. Staff will be able to track any pattern of change that might indicate that the house is structurally unstable. Non-specialist staff should use our Guidance to help identify indicators of possible structural stability problems. Where staff have concerns, they should ask a competent professional to carry out a detailed assessment.”
[213] The Defender was not assessing the appeal properties as part of a house condition survey. It was assessing them for enforcement purposes. The Defender was considering taking enforcement action when it instructed Mr Turnbull. Mr Turnbull carried out no more than a walk round survey. He did not even carry out a walk through survey as he never entered any of the appeal properties.
[214] As stated in the Guidance, where a local authority is considering possible enforcement action it is able to monitor the property over time. The Defender did not do so. On the key issue of whether or not the building is moving, the Defender’s evidence is inevitably limited because the Defender did not have anyone track the building over time. It seems to be very straightforward to monitor movement in a building over a period of time, and I cannot understand why that was not done in this case, even for part of the period between the serving of the demolition orders and this hearing. Whilst there was much evidence of cracking, of the various theories as to the causes of the cracking, and of the likely consequences of the cracking, there was little evidence before me as to whether or not the cracking was recent, historical and/or progressive. Monitoring of the cracking and of any movement in the building would have been of great assistance in this case, and without such evidence I am left in the unsatisfactory and regrettable position of simply considering the opinions of the various experts who viewed the cracking.
[215] The difficulty with Mr Turnbull’s evidence is that it is tainted by his acceptance that almost from the outset he had concluded that the roofs were moving due to corrosion expansion, and he looked for evidence to support his conclusion. As I commented earlier, his search for such evidence was perhaps to the exclusion of other evidence pointing in a different direction.
[216] Even if I had been prepared to accept Mr Lindsay’s argument (which I do not) that for a house to be structurally stable it must show no signs of recent movement, that would not take the Defender very far. I am unable to prefer one opinion over another on this crucial issue of current movement of the buildings, and that leaves me in the unsatisfactory position of finding that there is clear evidence that the buildings have moved, but insufficient evidence before me to enable me to conclude the buildings have recently or are presently moving. It therefore has not been proved that the buildings within which the appeal properties are situated are currently moving.
Conclusions
[217] Demolition orders were served in respect of the appeal properties on 26th June 2014. They were served on the premise that the properties fell below the tolerable standard by reason of the buildings within which the properties were situated were structurally unstable. The decision to serve the demolition orders was based inter alia on the reports from ATK Partnership and from Stanger Testing Services Limited.
[218] In considering the issue of tolerable standard, the Defender was obliged to have regard to Guidance issued by the Scottish Ministers, “Implementing the Housing (Scotland) Act 2006, Parts 1 and 2. Advisory and Statutory Guidance for local Authorities”. Chapter 4.11 of that Guidance indicates that a walk through inspection of a property would be suitable for a local house condition survey, whereas for an examination of a house for possible enforcement action based on its structural stability, a more detailed analysis would be required, and that might include monitoring the property over a period of time.
[219] When serving the demolition orders the Defender had not adequately investigated the condition of the properties. The Defender relied on Mr Turnbull’s report, but Mr Turnbull had not even been inside any of the appeal properties. He had not even carried out a walk through inspection of them. He was not aware of the purpose of his limited inspection or of the extent of his instructions.
[220] The Defender served the demolition orders on the basis the buildings were structurally unstable due to movement of the roof caused by corrosion expansion of the embedded steel. The Defender claimed that corrosion of the steel ribs was the major cause of corrosion expansion of the roof slab and the demolition orders were served on that basis.
[221] The roof and walls of the appeal properties’ buildings had clearly moved and there was evidence of extensive cracking to support that. However;
i. The cause of any movement of the roof and walls had not been established. It had not been proved the movement was caused by corrosion expansion of embedded steel within the roof structure. Mr Turnbull believed the roof construction was one of pre-cast concrete slabs, when in fact it was concrete poured in situ, and his statement that the cracking of the roof followed the pre-cast concrete slabs was incorrect. Further, when the correct construction of the roof was established, the Defender maintained its position on the basis that embedded steel ribs within the poured concrete was the cause of the corrosion expansion. That ultimately was not supported by the evidence of any of the experts who inspected the embedded steel ribs, and they gave evidence of noting only surface corrosion. Even the Defender’s expert, Mr Turnbull, departed from his original opinion that corrosion expansion of the steel ribs was the main cause of movement of the roof slab, and he stated that the corrosion evident on the steel ribs would not generate sufficient lateral force to cause movement of the roof slabs. Mr Turnbull in evidence therefore no longer supported his original opinion as to the cause of movement of the roof slab, and he did not support the Defender’s case on record.
ii. Mr Turnbull said it was corrosion of the steel loops that was the greater risk. That however was not the Defender’s case on record. In any event there was no satisfactory evidence of corrosion of the steel wire loops. Mr Turnbull’s evidence on that issue was based on a very limited inspection of two small areas.
iii. When the movement in the buildings had taken place was also not established. It has not been proved that there is any current movement in the main structural elements of the buildings.
[222] I am satisfied there was no proper basis for the Defender’s decision to serve demolition orders in respect of the appeal properties. The properties were not adequately inspected; the expert evidence relied upon was based on a false assumption as to the roof structure; there was speculation as to the extent of corrosion expansion in the roof slabs; there was no evidence of corrosion expansion of the embedded steel ribs; the cause of movement of the walls and gables had not been established; and there was inadequate investigation of any current movement in the buildings.
[223] Debonding: – the theory of debonding was raised long after the demolition orders were served. It was not raised until December 2015, and it was only supported by Mr Turnbull. I do not accept this issue was thoroughly investigated by the Defender, or that there was an adequate evidential basis for it. Mr Turnbull’s conclusion on this was based on his interpretation of small air gaps between the concrete and the steel. I found Mr Turnbull’s evidence and reasoning in relation to the theory of debonding not to be persuasive as to a possible cause of a structural issue with the roofs of the buildings. Mr Turnbull’s opinion was based on (a) a very limited inspection of a very small sample of steel and concrete, (b) evidence he had already used to support his earlier theory of corrosion expansion, (c) evidence he had earlier ignored as it did not support his earlier theory in relation to corrosion expansion, and (d) observations by him made at a time when he was considering a different theory. Other experts viewed the properties on various occasions, and none of them supported the theory of debonding as a significant issue. It has not been proved there is extensive debonding present within the buildings.
[224] In summary, the Defender departed from its original position that corrosion expansion of the embedded steel ribs was causing the roof slabs to move. Their expert, Mr Turnbull, said the main problem was with the embedded steel loops of wire. That was not the Defender’s position on record, and was not pursued by the Defender. The Defender therefore had no evidence to support its position that corrosion expansion of the embedded steel ribs was causing the roof slabs to move, or was causing any cracking in the building or other structural defect. Further, in respect of the Defender’s second case of extensive debonding, the evidence presented was not persuasive of its existence, such as would render the roofs structurally unstable. The cause of any movement in the roof slabs and the cause of any cracking to the buildings was not proved.
[225] The Pursuers accepted that the legal onus of proof lies with them and that the onus is on them to show that the properties are not structurally unstable by reason of either corrosion expansion or debonding. I am satisfied the Pursuers have done so.
[226] In any event, I have to consider the issue of tolerable standard de novo. I have to consider all of the evidence placed before me and make a decision that I think “just”. For the reasons given above, I am satisfied there is no evidence before me to satisfy me to the required standard that the roofs are moving due to corrosion expansion of the embedded steel ribs, or there is a risk to their structure caused by debonding. Corrosion expansion was the Defender’s reason for initially serving the original orders, and then latterly, corrosion expansion and debonding, for maintaining that they should remain in place.
[227] There was no other case put forward by the Defender as to why the properties might otherwise be structurally unstable and therefore not be of tolerable standard. On that basis, I find the evidence before me does not prove to the required standard that the roofs of the properties are structurally unstable by reason of corrosion expansion of the embedded steel or debonding, and therefore does not prove the properties are not of tolerable standard. That being the case, the demolition orders require to be quashed.
[228] Even if the evidence had proved there was corrosion expansion of the embedded steel and/or debonding, it would still require to be proved that as a consequence thereof, the properties were not structurally stable.
[229] With regard to structural stability –
i. I do not accept the Defender’s submission that it is simply the presence of recent movement of the structural elements of a building that renders a building structurally unstable. I prefer the Pursuers’ interpretation of Chapter 4.7 (supported by Chapter 4.10), which provides that it is the visible signs of potential instability that the assessor should look for to consider the stability of a building. I am satisfied it is necessary that consideration be given as to the possible consequences of any recent movement, rather than simply its existence. Even if however I was prepared to accept the Defender’s submission, it has not been proved there is any current movement in the buildings and, therefore, on the Defender’s submission, the buildings would be deemed to be structurally stable.
ii. The risk that requires to be considered is the risk of partial or total collapse (Chapter 4.7). I do not accept the Defender’s submission that it is the main structural elements of a house that are required to be at risk of partial or total collapse. The Guidance is quite clear. Consideration has to be given to the possibility that the house may be at risk from either partial or total collapse (Chapter 4.10 and Chapter 4.14). To find otherwise would mean that if part of a property collapsed, e.g. part of the overhang, the building would be deemed to be structurally unstable. The Defender was not prepared to submit that was the case.
iii. Mr Turnbull said the structural elements of the buildings were moving. He accepted however they were not currently failing. He considered the buildings to be safe for between five and ten years. It has not been proved that there is any current movement in the main structural elements of the buildings. It has not been proved that the structural elements are liable to partial or total collapse. Importantly, it has not been proved that the properties are at risk from partial or total collapse.
[230] Whilst maintaining the buildings were structurally unstable, Mr Turnbull stated they were safe. His evidence on this was very confusing. Ultimately, Mr Turnbull’s position was that the buildings, within which the properties were located, would remain safe for between five and ten years. The Defender’s position was that a building that would be safe for between five and ten years could still be structurally unstable. I do not agree. The structural stability and the safety of a building are inextricably linked. The introduction to Chapter 4 of the Guidance states, “4.2….. Instability in the structure of a house is an obvious threat to the occupants’ safety.” If a building is deemed to be safe for the next five to ten years, it clearly is not liable to partial or total collapse.
[231] I am satisfied the evidence before me did not provide proof to the required standard that the properties were not structurally stable.
DECISION
[232] I sustain the Pursuers’ First plea in law, repel the Pursuers’ Second plea in law, and in doing so quash the demolition order in respect of the property at Flat 3/3, 19 Robert Street, Port Glasgow, repel the Defender’s First, Second, Third and Fourth pleas in law, meantime reserve the question of expenses for further submission.
[233] This hearing of the six cases was never intended to be a test case for the hundreds of other cases that are presently sisted. It was hoped however that this hearing would explore the issues in sufficient detail so as to assist the resolution of many of the remaining sisted cases. My concern is that having heard the evidence in this hearing that might not prove to be the case. I found the Defender’s position on record to be confusing and contradictory. The evidence led did not support their position on record. Whilst I am not aware of the evidence held by the Defender relating to the other properties within the Clune Park estate, and therefore I am not aware of the basis on which it was decided to serve hundreds of demolition orders, I would have grave concerns with any decision to serve demolition orders in respect of properties which had not been inspected.
[234] Whilst the Pursuers have satisfied the legal onus of proof in this case, I must emphasise that this decision should not be taken as a declaration of structural stability for any of the appeal properties. The conclusion of this process has established that it was not proved to the required standard on the evidence laid before me that these buildings were structurally unstable due to corrosion expansion or debonding.
[235] A great deal of time and expense has been expended in bringing these cases, and that includes a great deal of court time and resources. It is therefore extremely disappointing that more was perhaps not achieved in this process. It was hoped, no doubt by both sides, that many questions would be answered, and that those answers might well assist in resolving many issues in the sisted cases. I would hope that if the sisted cases are to be brought forward to a hearing, consideration will be given to some of the comments I have made in this decision.
Derek J. Hamilton
Sheriff of North Strathclyde at Greenock
18 August 2016