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RAAC was used in a range of building types during the period of peak usage from 1950 -1990
Reinforced Autoclaved Aerated Concrete (RAAC) is a lightweight form of concrete. It is aerated and there are no coarse aggregates in RAAC, meaning it has significantly different properties and structural behaviour to traditional concrete. It is reinforced with steel bars which run the length and width of the material.
RAAC was used in buildings from the late 1950’s until the early 1990’s. It was used mainly for roofing, but also occasionally in walls and floors. RAAC is most commonly found in flat roofs, but its versatility and low weight meant that it was a popular building material for a wide variety of purposes throughout much of the middle to late 20th century.
RAAC was a common construction material in public buildings such as schools and hospitals from around 1950 until 1990 when UK and European building regulations called for more stable and durable materials to be used. However, RAAC surveys have revealed that its use continued into the 2000s in some cases.
There are no aggregates and an abundance of voids in RAAC, meaning that it is not as strong as other forms of concrete, is more vulnerable to water ingress and collapses under its own weight due to lack of structural integrity. Additionally, variations in the manufacturing quality of RAAC meant that in some boards, the internal steel reinforcements didn’t reach the end of the board. This means when these boards were laid in place with a support at either end, the only thing holding the weight of the board, as well as any surrounding materials or fittings, was the fragile RAAC itself. As a result, RAAC boards can eventually deform under their own weight due to a lack of structural integrity.
In 2018, RAAC roof boards collapsed in a school in Kent. The collapse occurred over a staff room, not a classroom, at a weekend and no one was injured. However, there have been several more incidents since 2018. These collapses sparked renewed concerns about RAAC structures nationwide.
Now, owners or managers of buildings that may contain RAAC are advised to contact an RAAC surveyor such as EMS to locate any RAAC and advise on the next steps.
RAAC is not linked to health concerns in the same way that materials like asbestos are. It does pose a risk of structural collapse, however, and is a potential safety hazard if concrete surveys are not conducted.
RAAC itself does not contain asbestos. However, it was used commonly between the 1950s and 1990s which is a period when asbestos use was prolific, meaning that buildings which contain RAAC are also likely to feature asbestos.
So, when carrying out any RAAC survey or remedial work, asbestos surveys will also be legally required to make sure asbestos is not accidentally disturbed.
For the untrained, RAAC can be very difficult to identify. The best way to assess whether your building contains RAAC is to contact an experienced RAAC surveyor like EMS.
They will be able to accurately identify any RAAC and offer recommendations for suitable next steps.
A RAAC survey is the first step in resolving any RAAC issues at your premises. EMS Surveyors will attend your site and identify possible RAAC materials using a non-intrusive visual inspection.
Our surveyors follow the guidance provided in the Department for Education’s ‘Reinforced Autoclaved Aerated Concrete (RAAC): Identification Guidance’ as well as the Institution of Structural Engineers’ ‘Reinforced Autoclaved Aerated Concrete Panels Investigation and Assessment’ document.
Following the survey, the RAAC surveyor will issue a report. This initial report will contain a list of possible RAAC materials at the premises as well as professional recommendations for what to do next.
If RAAC is present, we may suggest further surveying such as structural surveys to determine the condition of any RAAC materials and conduct risk assessments. You will then be issued with further reports which may indicate the need for RAAC remedial works.
EMS employs teams of qualified RAAC surveyors who can help you accurately identify RAAC at your premises and offer practical next steps in accordance with official guidance as well as rigorous internal processes. They are also all BOHS P402 trained asbestos surveyors.
For a complete and safe process, we also offer UKAS-accredited asbestos surveys to help you spot and manage any asbestos containing materials that might surround the RAAC, preventing them from posing further risks.
EMS does not provide structural assessments or offer legal advice. Further RAAC surveys may be required.
To book your RAAC survey or other assessments, call our team now on 0800 3581100, email us at info@emsgroupuk.com or fill out our contact form.
No, RAAC does not contain asbestos. However, it commonly features in properties constructed when asbestos was legal, meaning that buildings which contain RAAC frequently contain asbestos too.
RAAC is often found in the form of concrete boards in flat roofs but identifying it can be tricky without proper training. The best way to identify RAAC is with RAAC concrete surveys.
RAAC was used in buildings between the 1950s and the 1990s, when structural concerns began to emerge.
Despite not posing any health risks in the way that asbestos does, RAAC is potentially dangerous because it is liable to collapse in some cases.
Yes. RAAC was banned in the UK in 1996 and across the EU in 2006. The bans followed increasing concerns over structural integrity and several building collapses.
RAAC planks will be light grey in colour and have a porous texture with no aggregates. However, be very careful when assessing RAAC materials as they may be in poor condition or even coated with asbestos containing materials.
No. RAAC does not contain any asbestos and does not pose the same health risks. However, RAAC may be coated in asbestos containing materials such as asbestos paints, asbestos plaster or textured asbestos coatings like Artex.
