Reinforced Autoclaved Aerated Concrete (RAAC)
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Reinforced Autoclaved Aerated Concrete (RAAC)

Date published

Information on Reinforced Autoclaved Aerated Concrete (RAAC).

RAAC was a building material used in some buildings to form roof planks, wall panels, and sometimes floor planks, between the mid-1950s and mid-1990s.

Managing structures with RAAC

We have established key action to support building owners/ managers.

The following are suggested steps that building owners/ managers who are responsible for the safety of buildings should follow. This will enable building owners/ managers to address any issues relating to reinforced autoclaved aerated concrete (RAAC) that may be present in their structures:

  1. Identification – Not all buildings built between 1950 to mid-90s will have RAAC. It is therefore important to establish if they are present in your building. Identification can be undertaken by an experienced estate/ maintenance manager/ or building owner. The guide (below) has been created to enable managers of educational buildings to identify if their buildings have RAAC. However, if you are unsure then you can contact a professionally registered structural engineer or surveyor to identify if RAAC are present. To note they do not need to be an expert in RAAC to identify if the building has RAAC

  2. Assessment – Once you have established that RAAC has been used, your building will need to be assessed to understand what, if any, risk there is and if any immediate temporary remedial work is required. IStructE Chartered and Incorporated-Members would be competent to assess your structures.

  3. Solutions - Competent structural engineers will need to evaluate all the information (which will include a detailed site inspection) and propose any remedial works to be completed.

Competent IStructE Chartered and Incorporated Members will have experience of assessing structures, using their engineering judgement and providing solutions for different types of buildings.
All IStructE Chartered and Incorporated Members have signed up to the Institutions Code of Conduct, and Members are reminded that compliance with the Code of Conduct insists that Members:

  • Must undertake only those tasks and accept only those appointments for which they are competent

  • Operate within their area of competence 

  • Must maintain their competence through continuing professional development, such as keeping up to date on the latest guidance on RAACs

The Department for Education's decision in August 2023 to close schools with suspected RAAC has given prominence to the issues around RAAC.

Building owners in the public and private sectors are assessing their stock and contacting members to assist them.

The Institution has assembled a body of resources to help members understand the material and the course of action to take when assessing its condition.

For more information on how to join the RAAC open study group:

Find out more

Useful references


Further information and resources

Image showing a brick of building materials

IStructE statement & FAQs: Reinforced Autoclaved Aerated Concrete (RAAC)

The latest RAAC guidance and how to mitigate risk moving forward.

Date – 25 October 2023
Author – IStructE
<h4>Reinforced Autoclaved Aerated Concrete (RAAC) panels: Investigation and assessment</h4>

Reinforced Autoclaved Aerated Concrete (RAAC) panels: Investigation and assessment

This free guidance provides identification and remediation solutions for Reinforced Autoclaved Aerated Concrete (RAAC) planks. RAAC has been used in building structures in the UK and Europe since the late 1950’s, most commonly as precast roof panels in flat...

Date – 7 March 2022
Author – RAAC Study Group
Price – Free
<h4>Reinforced Autoclaved Aerated Concrete (RAAC) Investigation and Assessment – Further Guidance</h4>

Reinforced Autoclaved Aerated Concrete (RAAC) Investigation and Assessment – Further Guidance

This report provides further guidance on the critical risk factors associated with RAAC panel construction. It includes a proposed approach to the classification of these risk factors and how these may impact on the proposed remediation and management of RAAC....

Date – 17 April 2023
Author – RAAC Study Group
Price – Free
Image showing a brick of building materials

RAAC essentials for structural engineers

Learn how to identify, assess, manage and remediate reinforced autoclaved aerated concrete (RAAC) defects in buildings.

Date – 11 March 2024
Author – Various
Price – £0 - £325 + VAT

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Date – 3 October 2023
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