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What is RAAC?

Reinforced autoclaved aerated concrete (RAAC) is a lightweight material that was used mostly in flat roofing but has also been used in the construction of walls and floors, mostly between the 1950s and 1990s.

RAAC is a material that has been used in the construction of buildings including schools, hospitals, and other private/public sector buildings. In all instances, the need to identify whether RAAC materials are present in buildings is vitally important.

The Health and Safety Executive says “RAAC is now beyond its lifespan and may “collapse with little or no notice”.

Although called ‘concrete’, RAAC is very different from traditional dense concrete and, has been used as part of construction projects because of the material’s lightweight thermal properties.

Because of how it was made, RAAC is a cheaper alternative to standard concrete, quicker to produce, and easier to install, however, its structural behaviour differs significantly from traditional reinforced concrete, which results in it being less durable, with a lifespan of around 30 years. As it is aerated, it is susceptible to structural failure when exposed to moisture. If that happens, any embedded rebar reinforcing RAAC can also corrode, and weaken.

“Owners now need to carry out assessments of their buildings and assets to understand whether RAAC is present”.

If you are unsure how to identify whether you have RAAC in your building, JNP Group can carry out the initial inspection for you. Once the survey has been completed we can issue a confirmation note advising if it is present or not.

“If you are concerned your building may contain RAAC, we can provide expert guidance on its presence”.

To address these issues effectively, it is easier to work with experienced structural engineers who are knowledgeable about RAAC.
JNP Group not only provides expertise with this type of work, but we also cover the entire UK with a network of 7 offices. With over 110 engineers, our team is on hand to attend the site quickly and will efficiently provide an initial assessment of the presence of RAAC.

• If RAAC planks are identified and there are signs of spalling and/or deformation occurring, we will provide a technical report and a remedial works proposal.

• If RAAC is present, we will provide a technical report and recommendations for the next steps which may include a maintenance and monitoring program where we can revisit your site and flag up any deformation that may occur over time.