What is RAAC?

Reinforced Autoclaved Aerated Concrete (RAAC) is a type of lightweight building material that was used in the construction of schools, colleges, community centers, and other public buildings from the 1950s to the mid-1990s.1. This material is composed of a blend of cement, lime, water, and an aeration agent. The amalgamation is poured into moulds and subsequently exposed to high pressure and heat, a process known as autoclaving. This results in the formation of a sturdy, porous, and lightweight substance2.

While RAAC offered numerous benefits like its cost, lightweight and thermal insulation characteristics, it has also given rise to concerns and challenges for various institutions, including educational and public buildings.

Structural Integrity and Safety Concerns

One of the foremost concerns with RAAC is its structural integrity. Buildings constructed with RAAC walls and structures have faced questions about the material's long-term durability. This has prompted an increased emphasis on reinforcing and retrofitting RAAC-built buildings to ensure public safety. This heightened focus has led to the HSE commenting: ‘RAAC is now beyond its lifespan and may "collapse with little or no notice"3.

Environmental and Health Considerations

RAAC is celebrated for its environmentally friendly nature due to its low carbon footprint and energy-efficient production process. However, it is crucial to consider the potential health risks when RAAC is improperly handled or damaged. Schools, colleges, community and other public buildings have had to address concerns regarding dust emissions, which can pose respiratory health risks, especially during construction, renovation, or repair projects.

Maintenance, Repairs & Valuations

Maintenance and repairs of RAAC structures can be more complicated and costly than traditional construction materials. Often, the challenge lies in finding skilled contractors and specialised materials to address RAAC-specific issues, making it particularly challenging and expensive. This could potentially affect future rebuilding valuations used to reinsure buildings, potentially leading to underinsurance.

Legal requirements

The government has declared that the cost of repairing areas affected by RAAC in schools will not be borne by the schools themselves. However, it has been confirmed that the inspection of all 600 potentially impacted schools will extend until December 2023, with additional time required for the actual repairs to take place. The shared responsibility between schools and the government remains paramount in ensuring the safety of both students and staff4. Furthermore, the inspection of structures using RAAC will also be extended to public buildings to ensure the health and safety of the public.

Under the Health and Safety at Work (etc.) Act 1974, employers are obligated to safeguard the health and safety of their employees and individuals who may be affected by the employer's operations, even if they are not employees. Violations of these regulations can lead to criminal investigations and resultant penalties5. In this case, schools, community and other public buildings must ensure they are protecting members of the public against this danger. By conducting regular risk assessments, schools, community, and other public buildings can effectively demonstrate the controls and mitigations they have implemented to safeguard the public against this potential hazard.


If you oversee central and local government building management, maintenance, or modifications, it's essential to determine if your buildings contain RAAC and take the necessary steps to ensure their safety.

The Department for Education (DfE) and Local Government Association have released helpful documents that you can use if you have either identified or suspected the presence of reinforced autoclaved aerated concrete (RAAC) within your structures6.

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The sole purpose of this article is to provide guidance on the issues covered. This article is not intended to give legal advice, and, accordingly, it should not be relied upon. It should not be regarded as a comprehensive statement of the law and/or market practice in this area. We make no claims as to the completeness or accuracy of the information contained herein or in the links which were live at the date of publication. You should not act upon (or should refrain from acting upon) information in this publication without first seeking specific legal and/or specialist advice. Arthur J. Gallagher Insurance Brokers Limited accepts no liability for any inaccuracy, omission or mistake in this publication, nor will we be responsible for any loss which may be suffered as a result of any person relying on the information contained herein.