18 October 2023

Reinforced autoclaved aerated concrete, or ‘RAAC’, was invented in Sweden in the 1930s. It is a precast concrete material, reinforced with steel bars. Its manufacturing processes leave the concrete material filled with air bubbles, with the result that it weighs substantially less than other precast concrete. RAAC was used widely in Britain from the 1950s until the 1990s, particularly in the construction of flat roofs – though it was also used in floors and walls.

According to the British Research Establishment (BRE), RAAC has a lifespan of 30 years. As such, it is believed that more or less all RAAC panels in Britain are now operating beyond (in many cases well beyond) their lifespan. It is also understood that RAAC’s integrity can be compromised where it is exposed to water over a period of time – leading to corrosion of the steel bars. Water exposure might arise due to maintenance issues or subsequent works. There may also be instances where subsequent works have involved cutting through the RAAC panels, impacting on their integrity. 

Safety concerns arising from RAAC are nothing new, but they hit the headlines again recently when, on 16 August 2023, the Health & Safety Executive (HSE) advised that RAAC is life-expired and liable to collapse with little or no notice. This led to the closure of buildings at over 100 schools, nurseries, and colleges in England, just days before the start of the new school term.

RAAC in Scotland

In September, RAAC was confirmed to be present in 35 schools across 16 Council areas in Scotland. The Scottish Government stated that this posed no immediate risk, citing mitigations which had been taken to ensure safety. The number of schools found to be affected has since risen to 40.  Recently, West Lothian Council announced a £35 million plan to build replacement classrooms at St Kentigern's Academy, where RAAC was discovered last year.

Although media attention has largely been focused on schools, RAAC is also present in a much broader range of properties.

In the NHS, investigations into the presence of RAAC are ongoing. A desktop review by the Scottish Government identified that 254 NHS buildings north of the border had two or more characteristics which are consistent with the presence of RAAC. The Scottish Government has instructed specialist engineers to identify which buildings actually contain RAAC, and to make recommendations for treatment or removal.

Another area of concern is social housing. At the beginning of October, Aberdeen City Council stated that RAAC is likely to be present in around 500 council homes in Balnagask. A freedom of information request has also revealed that at least 43 council houses in Edinburgh contain RAAC.

Legal liabilities

The first priority for all stakeholders will be to identify the presence of RAAC in buildings and ensure that appropriate safety measures are put in place.  Naturally, though, thoughts will ultimately turn to the claims position.

Claims against those involved in originally specifying and using RAAC for construction are likely to face a number of complications, not least because of the passage of time since the works took place. The company responsible for specifying/using RAAC may no longer exist. Technical information from the project may not have been retained. Prescription and limitation (i.e. time bar) is also likely to be a significant factor – and this is an area where there are important differences between Scots law and the law of England and Wales.

To the extent that claims are not time barred under statute, there may be relevant contract provisions fixing a date after which claims may not be brought (for example, parties will often agree a limitation period of 12 years from practical completion). There are also commonly limits on the period during which parties are obliged to maintain professional indemnity insurance.

If all this is overcome, a claimant will need to prove a breach of duty which caused it to suffer a loss. Issues to be addressed will include whether the target of the claim was actually at fault for specifying or using RAAC, having regard to the state of industry knowledge at the relevant time, and the fact that it was being widely specified for use. On causation, questions will arise about whether current safety issues are due to the original construction, or whether they arise from a separate matter such as maintenance failures or intervening repairs/alterations. There is much for parties and legal advisors to consider.

Claims may also be contemplated against parties involved in maintenance, alterations, repairs or surveys – based on negligent work, or breach of a duty to warn about the presence or condition of RAAC. Such claims will likely give rise to interesting issues around the extent of duties owed, and the extent to which costs now being incurred in relation to RAAC are a loss attributable to breach of those duties.

Landlords and tenants (in both the commercial and residential sectors) will doubtless be seeking advice about their respective legal responsibilities, and stakeholders also will need to bear in mind their obligations towards persons entering premises (for example, in terms of workplace health and safety, and occupiers’ liability legislation).

The situation is still unfolding, but clearly RAAC presents significant issues, with which government, industry, insurers and lawyers will be grappling for some time to come.

For more information on this issue, or any queries relating to construction and engineering claims, please contact: 

Michael Collins, Senior Associate and Solicitor Advocate: mco@bto.co.uk / 0141 221 8012

Kate Ross, Trainee Solicitor: kro@bto.co.uk / 0141 221 8012