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RAAC and Ruin: The Crumbly Concrete Crisis

22 September 2023

  • For more information:
  • Senior Associate
  • T: 0141 221 8012

Reinforced autoclaved aerated concrete, or “RAAC”, has been hitting the headlines over the last few weeks. However, RAAC is nothing new, and neither are the concerns around the safety of buildings where it has been used in construction.

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.

Michael Collins
Michael Collins
Senior Associate

Concerns around the safety of buildings constructed with RAAC panels were being discussed as long ago as the 1990s, but a key moment came in 2018 when a flat roof at a Kent school collapsed suddenly. Fortunately, the collapse happened at a weekend, and no-one was injured.  However, this naturally gave rise to serious concerns, leading to the issue of various alerts and guidance.  These highlighted that RAAC in buildings was likely to now be well beyond its understood lifespan (30 years according to the British Research Establishment (BRE)), and that urgent checks should be carried out to identify RAAC in roofs, floors and walls.

On 16 August 2023, the Health & Safety Executive (HSE) advised that RAAC is life-expired and liable to collapse with little or no notice.  On 31 August 2023, days before the start of the new school term in England, the Department for Education announced that buildings at over 100 schools, nurseries and colleges had to close immediately due to critical safety concerns over RAAC.  

The nature and extent of the problem

At this stage, more or less all RAAC panels in Britain will be operating beyond (in many cases well beyond) their 30-year 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. 

Much of the recent discourse has been about schools, and at the time of writing the presence of RAAC has been confirmed in buildings at 40 schools in Scotland and 174 in England.

However, RAAC is also present in a much broader range of properties, including hospitals, courts and universities.  Furthermore, the issue is unlikely to be restricted to public buildings – there are indications that RAAC is present in some commercial and residential properties as well. 

Legal liabilities

The first priority for all concerned 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: / 0141 221 8012

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