The UK government did not heed advice regarding buildings containing potentially hazardous lightweight concrete, an issue that has since emerged in over 100 educational establishments, the Financial Times reported.

Government’s classification omits certain buildings

In 2020, an independent advisory group suggested that structures comprising reinforced autoclaved aerated concrete (Raac) be listed on a high-risk register under the government’s Building Safety Act – a suggestion that was not implemented.

The government’s criteria for “higher risk buildings” presently encompasses only buildings taller than seven stories with at least two residential units, as stipulated by the Act.

Had the advice been taken into account, there would have been a mandatory addition of all buildings with Raac to publicly listed by October 1 this year.

Building owners would subsequently have legal duties to declare structural safety problems and implement risk mitigation strategies.

Currently, various governmental departments are working to determine the prevalence of this lightweight concrete in both public and private sectors, following reports of its existence in diverse structures, including schools, hospitals, and office spaces.

Concrete concerns amongst stakeholders

A representative for the government stated: “These reforms complement longstanding duties on all building owners to address safety risks in their properties in a proportionate way.”

They continued: “If properly designed, manufactured, in good condition and with good bearing, Raac installations are considered safe.”

Notably, both Heathrow and Gatwick, two major UK airports, confirmed to the Financial Times the detection of this potentially fragile concrete on their premises.

Furthermore, the University of East Anglia opted to close its Norfolk and Suffolk Terrace housing due to government Raac guidelines, impacting numerous students.

Matthew Byatt, president of the Institute of Structural Engineers, stated: “Not knowing if a building contains weak or deleterious material is clearly a concern.”

He also highlighted: “Raac is a known risk material that needs to be assessed to determine whether it is safe, and if necessary to have mitigations put in place.”

Regarding the potential dangers, Byatt commented: “If Raac is present, it could be at risk of collapse with little or no warning.”

History and relevance of Raac

The Building Safety Act, enacted post the Grenfell Tower fire to address pre-existing safety lapses, was instituted in 2022.

Asked about the categorisation of “higher risk buildings”, Byatt mentioned: “We fully accept that it is the elected government that has to determine policy and therefore what becomes law.”

Another source affiliated with the institute believed the government was correct in its categorisation decision, suggesting that implementing a mandatory registry would be “very hard to legislate”.

Historically, this porous concrete was predominantly utilised in public buildings between the mid-1950s and mid-1990. However, it was also found in commercial private sector structures.

Both Heathrow and Gatwick, privatised in the 1980s, have been cognisant of the material prior to recent public awareness.

In conclusion, experts emphasise that structures containing Raac are primarily of concern if they’ve been inadequately maintained, which is predominantly the case in public buildings where maintenance investments have been inconsistent.

IFSJ Comment

Understanding the materials that constitute our buildings, especially those accessible to the public, is crucial.

The concerns surrounding Raac reiterate the importance of continued monitoring and adherence to professional recommendations.

By staying informed and proactive, we can ensure safer environments for all.