Reinforced autoclaved aerated concrete – safety risks and remedies for local authority clients

Until recently, reinforced autoclaved aerated concrete ('RAAC') was a term that was familiar mostly to structural engineers and surveyors. But following the collapse of a school roof that contained RAAC, it has been well-publicised as a dormant volcano that was buried beneath many buildings in the UK - and that is now showing signs of erupting. 

It is a particularly important topic for local authorities, which are likely to have large public buildings for which they are responsible. These are also the types of buildings where RAAC was more commonly used in construction. In addition to this, as public bodies, local authorities will be keenly aware of their responsibilities to tenants, staff and visitors. 

Consequently, it is critical for councils to ensure that they are aware of the issues and are taking appropriate steps in relation to any buildings that might contain RAAC.

What is RAAC?

RAAC is an aerated lightweight form of concrete that was developed in Sweden in the 1920’s. As it was cheaper and faster to use than traditional methods, it became very popular in the 1950’s, when many cities and towns were being rebuilt. It was seen as a tremendous positive, because it enabled the rapid and cost-effective construction of new public buildings in the post-war UK. This in turn allowed for the provision of services such as the NHS, and the growth of the economy. 

However, the same features that made RAAC so useful for quick construction also meant that it had a much more limited life span. By 2024, the RAAC in many 1950’s and 1960’s structures is therefore approaching, or has already passed, its best before date.

How urgent is the issue?

In August 2023, the Health and Safety Executive declared RAAC 'life-expired', and 'liable to collapse with little or no notice'. This provoked a flurry of concerns about the nature and lifespan of RAAC. 

In reality, the fact that a building contains RAAC in its roof, walls or floor does not mean that it has deteriorated automatically, nor that a collapse is imminent. RAAC has not been found to fail after any fixed time, and it is not as intrinsically dangerous as, say, asbestos. But if it was installed poorly, or has degraded due to inadequate maintenance or exposure, the risk is severe. 

Much will turn on how the RAAC was manufactured, installed and maintained, and the use of the building. For example, RAAC in a flat roof that has been exposed to water and frost is more likely to have suffered from poor maintenance.

Consequently, the mere presence of RAAC may not, by itself, be an emergency. But as there is no automatic prediction of the failure date, it is essential for local authorities to carry out urgent checks across all buildings that could contain RAAC, and to seek expert advice where it is discovered.

Where could RAAC be hidden?

The brightest glare of the media spotlight has fallen on buildings such as schools, hospitals, town halls and civic centres, which tend to be in the public eye, and to contain large numbers of occupiers and staff. However, other buildings that local authorities often own, such as car parks, shopping centres, office blocks and industrial estates, could also have been constructed by this method, along with the extension or augmentation of existing buildings.

Whether it is owner, landlord or tenant, every local authority should be taking advice to establish risks and understand liabilities.

What are the property implications?

From a property management perspective, the key questions are whether works are required, who must undertake them, and who will bear the cost. This is again of particular importance to local authorities, which have obligations to obtain the best value for money.

Local authorities should therefore be undertaking an urgent and thorough review to establish which buildings may contain RAAC. 

Where the council is the freeholder and is in occupation, any liability for works will rest with it.

Where there is a lease, in addition to undertaking a survey, the lease should also be reviewed, to establish factors such as:

• who has repairing responsibility for any relevant areas
• what maintenance, has been carried out
• how the building is to be inspected, and who can provide access
• whether there is any disrepair
• whether repairs would constitute improvements
• if the tenant is liable, when the liability will arise
• if the landlord is responsible, whether costs are recoverable under the service charge
• whether the Building Safety Act 2022 applies
• whether the insurer has any requirements

What are the health and safety obligations?

Statutory obligations to comply with health and safety laws and regulations run in tandem with contractual obligations. There may be differences in terms of liabilities and penalties for failure to comply, and so it is critical that all relevant persons are aware of them. This will be a key factor for local authorities, which have to maintain reputation and status.

As the issues with RAAC have been publicised widely, and the Health and Safety Executive has expressed concerns and published recommendations, the duty-holder for any building must take a pro-active stance to identify RAAC and assess its condition. The duty-holder is the party that is liable to comply with the legislation, and so could be a building owner; an occupier; or an employer of people in the building. 

Local authorities could fall into any one or more of these categories, and indeed are more likely to do so, given the broad and public nature of their property interests.

These duties apply regardless of whether the local authority is responsible for maintenance and repair. Whilst it might be self-evident that the council would have to take action where it is the building owner and occupier, or the landlord with responsibility for the relevant parts of the building, the council could still be liable under health and safety legislation even if the contractual obligations rest elsewhere. 

This means that, in buildings that contain RAAC, a local authority occupier is required to establish whether or not it can remain in occupation, even if it is not responsible for any works. The local authority will want to be able to persuade the regulator that it took steps to assess the risks and then to remediate the issues, to ensure that people in the building are safe. Failure to comply with this is a criminal offence.

Where a council has staff and visitors attending buildings that may contain RAAC, it should take urgent advice on:

• whether the building contains any RAAC
• the condition of the RAAC
• whether appropriate mitigation measures are in place, from monitoring to vacating
• who is liable to do the works and what steps are being taken
• putting that party on notice that it must carry out works
• if the council is liable, notifying tenants and occupiers as appropriate
• where there is a dispute over liability, what should be done in the short term while the issue is resolved
• whether other issues, such as asbestos, will be affected by any works, and the steps that should be taken to avoid this

Failure to do so could constitute an invitation to prosecution.

What should local authorities be doing?

Demonstrating proactivity and monitoring the position with each building carefully is critical for local authorities. In each case where a third party might be liable, if the costs are substantial, advice should also be sought on liability. 

In any event, very clear records of all inspections, decisions and activities should also be retained.

Councils should therefore be working hard to inspect properties that could potentially have an issue, and to put suitable mitigation strategies in place.