10.16 FOUR SCHOOLS OUTSIDE EDINBURGH WHICH SUFFERED DAMAGE IN HIGH WINDS

10.16.1 South Lanarkshire schools

10.16.2 In early January 2012 during a period of exceptionally high winds, external wall panels collapsed at two secondary schools, Trinity High School and Duncanrig Secondary School in South Lanarkshire. Fortuitously both schools were closed at the time of the collapse for the Christmas holiday period. These schools were built in 2009 under a PPP contract.

10.16.3 As shown in the photograph below, the Trinity High School collapse had a striking similarity to the collapse at Oxgangs School, with the corner brickwork panel of the external leaf of a gable wall separating from the internal leaf and falling from a height onto a playground below.

Image 26: Photograph of the collapsed panel at Trinity High School.

10.16.4 An extract from a structural report on the collapse at Trinity High School stated:

"The wall tie pattern evident at the collapsed outer leaf locations did not take account of the outer leaf movement joints and only provided ties at 900 centres vertically and not set out horizontally to provide the 225mm horizontal dimensions from the joint location.

The as-built spacing of cavity ties at the movement joints would lead to the wall ties near the joints being subjected to an increasing tensile and compressive loading compared with loads had the ties been installed to code spacing requirements. It should also be noted that the overall length of the two-part tie (400mm) in light of the cavity width of 330mm does not provide the minimum code requirement of 50mm embedment in the inner and outer leaves."

10.16.5 This last point is particularly important; if the same embedment had been provided to each leaf, this could only have achieved 35mm embedment which is 30% less than the minimum British Standard requirement of 50mm. In fact, for two-part ties a greater embedment of 75mm is recommended by leading wall tie manufacturers, making the defect potentially more serious.

10.16.6 At Duncanrig School, a brick panel on a gable wall collapsed inwards against the internal leaf of the cavity wall. A structural report on the event stated that the head of the brick panel did not appear to be restrained. In relation to the embedment of the wall ties it stated:

"It appears that the wall ties had significantly less than this 50mm and in some instances the ties were not embedded at all."

10.16.7 The following photographs, together with the comments below the photographs, are taken from the structural reports and show evidence of the lack of wall ties and improperly installed wall ties at Duncanrig School.

Image 27: Photograph from Duncanrig Secondary School. 'Note no ties or head restraints to inner face of outer brick leaf'.

Image 28: Photograph from Duncanrig Secondary School. 'Note wall ties with no embedment in outer brick leaf of cavity wall'.

10.16.8 Stirling Council

10.16.9 In May 2016, Balfron High School in Stirlingshire was partially closed after structural problems were identified. A wall at the school had been damaged during winter storms and after checks were carried out by engineers, issues with walls in the stairwell, gym and atrium were discovered. Stirling Council advised that defects had been discovered in relation to insufficient wall ties and lack of embedment of wall ties. The school which opened in 2001 was delivered under a PPP contract. The Inquiry was not provided with further details as to the extent of the defects.

10.16.10 Glasgow Council

10.16.11 The following paragraphs on Lourdes Primary School in Glasgow are based on information provided in evidence to the Inquiry as the structural report was not made available to the Inquiry.

10.16.12 At Lourdes Primary School, on the 3rd January 2012, during a period of exceptionally high winds, a wall at a high level partially collapsed, damaging the roof section onto which it fell. The section which came down was approximately 15 square metres in total.

10.16.13 This school was not procured under a PPP scheme but, most unusually, was built for the Council as part of a land swap deal with a major retailer, who procured the school through a design and build/turn-key arrangement, whereby the Council was provided with a completed school.

10.16.14 The structural engineering report concluded that there had been a lack of wall head restraints on the wall panel that had collapsed. Also, there was an insufficient number of wall ties and those that were there had not consistently adequate embedment.

10.16.15 When the walls were subsequently intrusively examined, similar defects were found on five other gable walls at the school. A two-part wall tie had been used where the cavity width was 300mm but in many cases, only one half of the two-part wall ties was found to be present. A number of walls were taken down and in large part rebuilt. Remedial wall ties, lateral ties and wall head restraints were installed where found missing and a number of windposts were added.

10.16.16 It was also noted in the Report that bed joint reinforcement which had been specified at 600mm centres, were found to have been installed at 900mm centres.