article: The wall at Oxgangs Primary collapsed during stormy weather in January 2016. A senior employee at the subcontractor that built it, VB Contracts, told the BBC the inner and outer walls were not constructed at the same time. Architecture professor Alan Dunlop said this "design issue" could have been the root of the problem at Oxgangs. VB Contracts went bust in 2010, but the BBC spoke to a former employee, who did not want to be identified, as part of the BBC Scotland Investigates: How Safe is My School? programme, which was broadcast on Monday evening. The collapse of the Oxgangs wall led to 17 schools across Edinburgh being closed over safety concerns. They have all since reopened. The schools had all been built or refurbished following a Â£360m deal between the city council and a private finance consortium under the Public Private Partnership 1 (PPP1) scheme. The lead contractor for the Edinburgh schools project, Miller Construction, was bought by Galliford Try in 2014. Miller Construction had outsourced some of the work to VB Contracts, which was responsible for the brick and blockworks at Oxgangs Primary, and built the wall that collapsed. Internal blockworks for such walls are generally built at the same time as the brick which forms the outside skin of the building. This allows the builder to ensure the two parts are properly connected, with wall ties in the right places. But the former employee said Miller Construction had told VB Contracts to build the internal wall at Oxgangs first so the building could be made water and wind tight as quickly as possible in order to allow inside work such as plastering to get started. It was the outer wall that subsequently fell down at Oxgangs school. Architect Alan Dunlop told the BBC the way the walls were built was therefore not "standard practice" and in his view was at the "root of the problems" at Oxgangs school. He said: "If you're going to do that, I would expect a method statement for that to be done. That's a design issue. It's not an add, it's not something you do ad hoc. And you have to do it properly and you have to specify the right wall ties for doing it. "In the evidence of the photographs that we have seen, that doesn't look to be the proper wall tie that you would actually use in circumstances like that." Mr Dunlop added: "The evidence is clear in the Oxgangs project. The wall collapsed and evidently it doesn't look as though it was safe at all. That's another whole shocking and worrying aspect of this whole process." In a statement, Galliford Try said it had contractual responsibility for four of the 17 Edinburgh public private partnership schools built 10 years ago. The statement added: "Work required to reopen those four schools temporarily closed has been completed and the schools opened on 24 May and 6 June 2016. "Throughout, Galliford Try's priority has been to ensure the children return to their studies at the earliest opportunity. We worked tirelessly with
summary: The collapse of a wall at an Edinburgh primary school could have been caused by the way it was built, a BBC Scotland investigation has found.