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Reinforced Autoclaved Aerated Concrete (RAAC): Guidance & Information Sources

Reinforced Autoclaved Aerated Concrete (RAAC): Guidance & Information Sources

The extent to which Reinforced Autoclaved Aerated Concrete (RAAC) is present in residential buildings and the risk levels presented is currently unclear, and we appreciate that media coverage, conflicting reports and misinformation may be leading to questions and concerns from clients and residents alike. RAAC is a form of lightweight concrete sometimes referred to as panels. It was used primarily in roof planks of some public buildings built between the mid-1950s and mid-1990s.

The Construction Leadership Council (CLC) in conjunction with the Cabinet Office and other government departments have set up the RAAC Industry Response Group. The group met up for the first time yesterday in early September 2023 and over the coming weeks will investigating scale and risks and developing further guidance. We are pleased to report that The Property Institute and our sector is represented on the group by Mark Snelling, our health, safety and fire consultant.

Whilst further investigation is carried out into the scale and risks, and guidance for the residential sector is developed, please be assured that The Property Institute is engaging with our technical colleagues and industry peers to help shape guidance specifically for managing agents, landlords and residents, which we will share with you as soon as any is available, particularly in relation to high-rise buildings and the Building Safety Act 2022. We are also in communication with the Building Safety Regulator at the HSE on this issue, so please look out for further updates.

Please ensure that, if you are undertaking any investigate or survey work, you seek advice to ensure that such costs incurred are reasonable and proportionate.

It would be useful if you could inform us whether you have completed any structural surveys in relation to an HRB and if so, whether the presence of RAAC was a consideration in the survey, and whether any RAAC was found. Please email jthorburn@tpi.org.uk with your findings.

There has been extensive media coverage on this issue, particularly for schools and other public premises, and whilst technical guidance is being formed, we wanted to provide you with some existing and updated sources of information and guidance from relevant and authoritative bodies and organisations, which may be helpful.

GUIDANCE FROM THE INSTITUTION OF STRUCTURAL ENGINEERS

The Institution of Structural Engineers (IStructE), who are leading on the technical aspect of the Industry Response Group’s response, have issued guidance about RAAC to enable building managers and their consultants to manage the situation, established a RAAC working study group, and created a list of professionally qualified structural engineers (Chartered or Incorporated Members) who have declared their experience in providing technical solutions for managing RAAC planks.

In a statement issued on the 1st September 2023 IStructE have said:

“If properly designed, manufactured, in good condition and with good bearing, RAAC installations are considered safe. However, the panels can creep and deflect over time, and this can be exacerbated by water penetration. A more recent incident indicated that if they have insufficient bearing and their structural integrity is compromised, they can fracture and collapse with little or no warning.”

Collaborative Reporting for Safer Structures UK (CROSS-UK), a confidential reporting system which allows professionals working in the built environment to report on fire and structural safety issues, have recently issued a report about a RAAC assessment that was carried out by persons who did not appear to have appropriate experience, potentially putting building users at risk of harm. The Key Learning Outcomes in the report for building owners, managers, surveyors, and other persons responsible for the safety of buildings are:

  • building users could be at significant risk of harm if incompetent assessments of RAAC are relied upon;
  • If RAAC is suspected, an assessment should be made by a Chartered Structural or Chartered Civil Engineer familiar with the investigation and assessment of reinforced concrete structures;
  • If RAAC is confirmed, a risk assessment of the building and its use is advised;
  • Risk assessments should have input from an engineer with appropriate knowledge and experience of RAAC; and
  • The Department for Education (DfE) publication, Reinforced Autoclaved Aerated Concrete: estates guidance, contains advice useful when appointing an engineer to assess RAAC

STRUCTURAL SAFETY GUIDANCE & REPORTS

Below, we’ve collated the most informative resources and guidance on RAAC, from The Institution of Structural Engineers (IStructE), The Department of Education (DfE) and Collaborative Reporting for Safer Structures (CROSS):

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BDC 311 : Dec 2023