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RAAC: guidance for employers and duty holders from a Health and Safety Law Perspective

On 31 August 2023, the Department for Education issued new guidance on the management of Reinforced Autoclaved Aerated Concrete (“RAAC”) in school buildings and other education settings. As a result of this guidance, and at a very late stage in the school summer holidays, over a hundred schools have been forced to vacate buildings known to contain RAAC and seek alternative venues to begin the autumn term.

The risk, however, is not exclusively related to education settings. Numerous public buildings built between the 1950s and 1990s contain RAAC, including libraries, council offices and even court buildings. Harrow Crown Court has been closed for up to nine months while RAAC is removed and replaced to ensure the safety and stability of the building, a decision which will have a substantial knock-on effect delaying criminal cases across London and the South-East to accommodate the overflow of cases. Concerns about RAAC are becoming increasingly widespread, and it appears likely to follow asbestos and aluminium composite cladding as the next problematic construction material. But what is RAAC and how can the risks associated with RAAC be managed?

What is RAAC?

RAAC is a lightweight, porous concrete, reinforced with metal. It is made using aluminium powder, which reacts with the water to produce carbon dioxide gas. This creates the bubbles that give RAAC its lightweight and insulating properties. RAAC was commonly used in the construction of schools and other (largely public) buildings in the United Kingdom from the 1950s to the 1990s. RAAC is commonly used in beams and, in particular, flat roofs. It is usually concealed, making it difficult to identify.

In and of itself, the presence of RAAC is not necessarily a problem. In many cases it is entirely fit for purpose but research from Loughborough University has shown that this is often not the case for RAAC manufactured in the 50s, 60s and 70s. Alarmingly, signs of deterioration can be extremely well-concealed, leading to the headline-grabbing risk of sudden collapse.

RAAC can suffer from manufacturing defects such as voids around the reinforcement bars, construction defects such as short bearing lengths and performance defects such as corrosion of reinforcement bars caused by environmental factors.

Because RAAC is lightweight and has relatively low density, if the metal reinforcement within it corrodes, it does not always result in the concrete cover breaking apart, so the corrosion can go unnoticed. One area of significant worry is corrosion at the end anchorage points. This can lead to the concrete panels shearing, often without notice or warning.

So why is this such an issue now?

Many RAAC buildings are now reaching the end of their approximately 30-year lifespan. The concrete has been exposed to moisture for many years, and it is starting to deteriorate. This is a particular problem in the United Kingdom, where the climate is wet and there is a lot of rainfall.

What should I do?

In the first instance, DON’T PANIC. Not every building from the relevant time period will have RAAC components. Guidance from the Government website and the Royal Institute of Chartered Surveyors will help you identify whether your building is in an at-risk category. If so, the buildings should be surveyed by a suitably qualified and competent surveyor to determine the existence of RAAC. In the meantime, conduct a risk assessment to ascertain whether the potentially affected building or parts thereof should remain in use.

Any RAAC found should be inspected for signs of deterioration and your surveyor, sometimes with the assistance of a structural engineer, will be able to make recommendations. Some panels will have intermediate supports put in place while others may require wholesale replacement.

What if we get it wrong?

The issues with RAAC having been widely reported, there is no escaping the fact that duty holders need to be proactive in identifying its presence.

As with any safety issues, protection starts with a risk assessment. In cases relating to alleged breaches of health and safety law, key factors include whether a sufficient risk assessment has been undertaken and, assuming that is has, whether any risks identified have been adequately mitigated.

Commercial premises owners/tenants and employers owe duties to building users under the Health and Safety at Work Act. This includes contractors, visitors and the general public. These duties apply regardless whether your organisation is in fact responsible for the maintenance of the premises in which it operates, so even in circumstances where you are not, the risk assessment should cover whether or not the building or area can remain in use. There is no single solution. A risk assessment will identify, for example, the relative risks of RAAC identified above a classroom and RAAC identified above an unoccupied storage area.

Ultimately, a duty holder who fails to mitigate against the risk posed by RAAC can be prosecuted. A sufficient risk assessment, coupled with professional advice, will go a long way towards preventing any sudden failure, ensuring the safety of building users and thus safeguarding the duty holder against criminal liability.

Contact a health and safety lawyer today

For further guidance and advice on Reinforced Autoclaved Aerated Concrete (RAAC) or for more information on health and safety law please contact a member of our team.


Your key contacts

Sam Harkness


Sam specialises in criminal and regulatory litigation, advising clients across a diverse range of sectors throughout the criminal and regulatory process, with a broader litigation practice in property, probate and agricultural matters.
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Bridget Sanger

Senior Associate

Bridget defends, represents and advises companies and individuals investigated and/or prosecuted in the criminal courts, with particular specialism in regulatory work surrounding agriculture and regulatory work surrounding care homes
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