How to manage and control the risks associated with reinforced autoclaved aerated concrete

RAAC (reinforced autoclaved aerated concrete) is a lightweight form of concrete used in roof, floor, cladding and wall construction in the UK from the mid-1950s to the mid-1980. 

Whilst commonly used in public buildings, RAAC has been found in a wide range of premises that are no longer in public sector ownership. Anyone with management responsibilities for buildings must determine if the building contains RAAC, and if so, its location and condition. 

If RAAC is present, steps must be taken to manage and control the risks associated with this building material.

• Building users could be at significant risk of harm if incompetent assessments of RAAC are relied upon
• If RAAC is suspected, an assessment should be made by a Chartered Structural or Chartered Civil Engineer familiar with the investigation and assessment of reinforced concrete structures;
• If RAAC is confirmed, a risk assessment of the building and its use is advised;
• Risk assessments should have input from an engineer with appropriate knowledge and experience of RAAC

Further information and guidance

• The Health and Safety Executive
• Welsh Government

Resources and guidance for RAAC:

• IStructE statement and FAQs: Reinforced Autoclaved Aerated Concrete (RAAC)  (1st September 2023)
• List of Structural Engineers (Chartered or Incorporated IStructE Members) who have declared experience in providing technical solutions for managing RAAC planks
• Learning outcomes from assessment undertaken by surveyor who was not competent or experienced with RAAC (August 2023)
• CROSS Report on failure of reinforced autoclaved aerated concrete (RAAC) planks – May 2019
• DfE Reinforced Autoclaved Aerated Concrete (RAAC):  Identification guidance
• March 2022: Reinforced Autoclaved Aerated Concrete (RAAC) panels: Investigation and assessment
• April 2023: Reinforced Autoclaved Aerated Concrete (RAAC) Investigation and Assessment – Further Guidance