Dangerous concrete found in 17 Scottish fire and police buildings The substance, known as RAAC, can cause roof collapse and poses a risk to staff and public safety
A substance that can cause roofs to collapse has been discovered in 17 fire and police stations across Scotland. The substance, known as reinforced autoclaved aerated concrete (RAAC), was widely used in the 1960s and 1970s but has since been found to deteriorate over time.
The Scottish Fire and Rescue Service (SFRS) said it has been aware of the problem since 2019 and has taken remedial actions to protect firefighters in those stations. However, it said permanent solutions are required as the stations are key locations for its operations.
Police Scotland said it has also found RAAC in ten areas of the roof of its Fettes headquarters in Edinburgh, as well as in two other buildings in Dundee and Perth. The force said it has removed staff from the affected areas and installed emergency pillars and safety nets to prevent debris from falling. It said it is planning to exit Fettes and relocate elsewhere in Edinburgh, as repairing the building is not economically viable
The issue of RAAC has also affected other public buildings in Scotland, such as schools and theatres. Forres Academy in Moray has closed and moved to remote learning after RAAC was found in the roof. Motherwell Concert Hall and Theatre has also shut down after RAAC planks were discovered in most of the roof structure.
The Scottish Liberal Democrat leader Alex Cole-Hamilton has called on the Scottish government to publish a full list of public buildings containing RAAC and to set up a national fund to assist with its removal. He said the government has failed to act on clear warnings and must urgently address the situation.
What is RAAC?
Reinforced autoclaved aerated concrete (RAAC) is a lightweight material that was used mostly in flat roofing, but also in floors and walls, between the 1950s and 1990s . It is a cheaper alternative to standard concrete, is quicker to produce and easier to install. It is aerated, or “bubbly”, like an Aero chocolate bar. But it is less durable and has a lifespan of around 30 years. Its structural behaviour differs significantly from traditional reinforced concrete. Moreover, it is susceptible to structural failure when exposed to moisture. The bubbles can allow water to enter the material. If that happens, any rebar reinforcing RAAC can also decay, rust and weaken. Because of this, RAAC is often coated with another material, such as bitumen on roofing panels. But this material can also degrade .
The potential safety issues of ageing RAAC were first reported in the 1980s and 1990s, when roof collapses led to buildings being demolished. The differences to traditional concrete – and the risks of RAAC use – were outlined as far back as 1961, around the time when Britain first began to use the material. The potential safety issues of ageing RAAC were first reported in the 1980s and 1990s, when roof collapses led to buildings being demolished. A 1996 government-funded report by the Building Research Establishment had found RAAC panels cracking in a housing development, and cracks and bends in panels installed in schools. It said that while there were no immediate safety risks, any RAAC panels in visually poor condition should be inspected every year. It recommended inspections every five years for those in good condition.