Reinforced Autoclave Aerated Concrete (RAAC)

Reinforced Autoclave Aerated Concrete (RAAC) has been identified as a significant issue for local and central government. HOP Director Adam Humphrey has been added to the IStructE group of members with RAAC experience. This means that HOP are able to advise on and assess structures that have issues relating to RAAC.

Below are some of our most recent projects involving issues with RAAC.

A Public Building in the South East

HOP were initially instructed to review an existing roof slab soffit for the installation of new suspended services. HOP undertook an internal visual appraisal of the roof soffit where it was then confirmed that the original roof panels were constructed in Reinforced Autoclaved Aerated Concrete. The RAAC planks were showing signs of local crushing, cracking, and significant deflection.

After an external visual inspection was carried out, it was advised that work be halted until a detailed survey was carried out and a remediation strategy be developed. HOP advised that the planks would need to be either replaced or strengthened. HOP were then instructed to undertake the design and detailing of additional support steelwork.

Further Education Facilities in the South East

After receiving requests from the Department for Education to review all of their sites for RAAC, HOP were instructed to provide structural reviews for all 6 of the sites across the Estates.

The inspection of each site consisted of a walkover with the member of the Estates Department at each of the sites to determine if RAAC had been utilised.

It was identified that RAAC was in fact used in an internal wall lining panel of a workshop. However, it was established after a review that as the RAAC wasn’t directly supporting roof finishes and had no significant weathering and therefore did not need immediate attention, though it will need periodic monitoring.

The other 5 sites were found to not have RAAC present in any of their estate buildings.

Government Building in South East.

HOP were instructed to investigate the roof structure after reports from a Health and Safety Specialist advised that the building could have been constructed using RAAC planks.

HOP initially undertook a visual inspection of the roof for any significant defects and also employed a specialist company to test samples of the roof to check adequacy.

Visual inspections confirmed that the roof slab was not formed in planks and therefore there was no presence of RAAC planks.

However, it was suggested that the roof slab was inspected on a periodic basis to ensure there was no deterioration over time.

If you think you might have RAAC present in your building, please contact us.