Potential RAAC panel failures could be catastrophic – comment

Colin Tait (Harley Haddow)

ENGINEERING consultancy Harley Haddow has commented in response to the ongoing story on school closures due to the presence of RAAC, a lightweight form of concrete used in the construction of schools, colleges and other buildings from the 1950s to the mid-1980s.

Colin Tait, Civil and Structural Director, Harley Haddow, said:

“It is surprising that this has suddenly become an issue, as the failure mechanisms of RAAC panels have long been discussed and on the radar of structural engineers. Across the UK, RAAC panels are present in a large number of buildings from police stations through to schools and hospitals. A collapse of these planks could be catastrophic, which is why we are seeing such rapid action being taken.

“From the mid-90’s, the UK’s Building Research Establishment was publishing information guides on RAAC identification, potential failure modes, maintenance regimes and remedial works – this was all off the back of RAAC failures in the 80’s.

“As recently as 2019, warnings by the UK’s SCOSS (Standing Committee for Structural Safety) of a RAAC panel collapse in a school brought a renewed light to the subject. Respective government bodies made building owners aware of these potential risks at that time.

“There are many reasons why these planks fail. Overloading, poor or limited plank support, excessive deflection and water ingress to name a few. Some of these flaws are down to poor design, poor construction, or simply down to poor maintenance. Cracking to the plank, particularly near its support and water ingress – whereby it turns the concrete, in essence, to a ‘sponge’ – were felt particularly worrying. Hidden behind false ceilings, collapse of these planks could be without warning and devastating.

“Presently the Department for Education August 2023 guidance advises restriction of access to spaces where RAAC has been confirmed. This is irrespective of the condition, the maintenance programme or inspection regime previously implemented.”

With over 30 years experience, Colin has expert knowledge in civil and structural engineering ranging from small refurbishments to multi-million pound developments.

Harley Haddow is a multi-disciplinary engineering consultancy with offices in London, Manchester, Glasgow, Edinburgh and Fort William.  The consultancy offers multiple services such as Civil and Structural, Energy and Sustainability, Mechanical, Electrical and Public Health (MEP), Net Zero and Building Research Establishment Environmental Assessment Method (BREEAM). 

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