Home News NFRC publishes RAAC Decking Safety Alert

NFRC publishes RAAC Decking Safety Alert

The guidance outlines the approach that should be adopted if a contractor suspects RAAC planks are present on a flat roof refurbishment, following the DfE’s announcement that schools with confirmed RAAC should no longer be open without mitigations in place.

Following the news that 104 schools have been told by the Department for Education (DfE) to vacate spaces or buildings that are known to contain reinforced autoclaved aerated concrete (RAAC) planks, the NFRC Technical Team, alongside CROSS and DLUHC, has produced a Safety Alert which outlines the approach that should be adopted if a contractor suspects RAAC planks are present on a flat roof refurbishment.

Filled with bubbles of air, RAAC is said to be about a quarter of the weight of normal reinforced concrete, and given its light weight, planks of RAAC were widely utilised for flat roofs.

When the material was still being used in the 1990s, structural engineers discovered that the strength of RAAC wasn’t standing the test of time. The porous, sponge-like concrete – especially when used on roofs – could easily absorb moisture, weakening the material and also corroding steel reinforcement within.

The risks of RAAC in schools and hospitals have been known for some time, and the issue was pushed further into focus in July 2018, when part of the roof at a primary school in Gravesend collapsed.

But ahead of the new school term, new guidance for education settings advises that any space or area with confirmed RAAC should no longer be open without mitigations in place. In a statement on the gov.uk, the DfE states: “New measures to minimise the impact of Reinforced Autoclaved Aerated Concrete (RAAC) in education settings have been published today, Thursday 31 August, by the government.

“While building maintenance is the duty of councils and academy trusts, new RAAC cases have reduced the Department for Education’s confidence that school and college buildings with confirmed RAAC should remain open without mitigations in place.

“As a result, following careful analysis of new cases, the department is taking the precautionary and proactive step to change its approach to RAAC in education settings, including schools. This decision has been made with an abundance of caution and to prioritise safety of children, pupils, and staff ahead of the start of the new term.”

Commenting on the situation, Tim Seal, Head of Construction at law firm Ridgemont, stated: “The impact of RAAC will vary case-by-case. Not all schools with RAAC need to close: the disruption experienced will depend on a case-by-case basis including what mitigations a school can put in place – and how quickly it can do so. 

“The government has been managing the risks associated with RAAC since around 2018 by providing guidance (and funding) for owners and managers.  However, some recent cases – including sudden roof failures – have caused it to decide that buildings containing RAAC should not stay open without extra safety measures being put in place. This can be considered as part of Government’s policy emphasis over the last few years on the safety of buildings, especially those occupied by more vulnerable parts of society.

“RAAC was used from the 1960s to the 1990s in various types of public buildings – not just in schools, in hospitals for example. Not all remain in the public sector today. It would be sensible for building owners and managers at risk of having RAAC in their buildings to contact a qualified structural engineer or building surveyor for advice.”

You can view the NFRC’s Safety Alert here.

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