Another roof structure to gain popularity in the 1950s are Timber Development Association (TDA) trusses. Last month, they were under fire after a ceiling collapse at Slains School in Aberdeenshire. The single incident has created nationwide fear of these trusses. They were constructed at a time when immaterial resources such as labor were extremely short due to the post-war boom. The Scottish government and local authorities have been alerted to potential issues with these roof structures, prompting a comprehensive inspection program.
TDA trusses make up Slains School, and 20 other schools in Aberdeenshire. Most recently, it experienced a ceiling collapse caused by a structural failure at the connection between the ceiling joists and the rafters above. Structural deficiencies and inadequate construction of the roof trusses were cited as causes for this collapse.
“Following a further review of findings, our structural engineer contractor has updated their report which attributes the ceiling collapse to a failure of the connection between the ceiling joists and the rafters.” – Aberdeenshire Council
The TDA trusses, constructed in an era of scarcity, have proved to be largely trustworthy for decades. A coordinated UK-wide investigatory postcard survey found no other reported ‘failures’ of this kind. The collapse at Slains School has cast a wider shadow with greater scrutiny and precautionary measures.
“The primary contributing factors were insufficient fixings, additional loading from modifications since the school was built, and workmanship during the original construction.” – Aberdeenshire Council
A year before the collapse, the Scottish government had prepared an extensive briefing note outlining the dangers posed by TDA trusses. In this exclusive, key update, we managed to get all other local authorities in Scotland! It is the intent of this communication to call attention to potential structural hazards with specific roof styles, encouraging careful consideration and preventative action.
In order to make sure the rest are safe, Aberdeenshire officials have launched an inspection program to assess all 12 other schools built with TDA trusses. Construction buckled under load. Structural engineers will be carrying out inspections in the coming weeks. They are going to inspect the roof systems and eliminate any potential hazards.
