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Reinforced Aerated Autoclaved Concrete (RAAC)

Frequently asked questions about RAAC.

Does the council have any public buildings with RAAC?

We are currently undertaking a survey across our entire property estate to identify the presence of Reinforced Aerated Autoclaved Concrete (RAAC). At this time it has been identified in four buildings and in line with guidance, precautionary works have been carried out.

What are the buildings?

Two schools, one community centre and one concert venue/theatre.

What is RAAC and why is it used in buildings?

Reinforced autoclaved aerated concrete (RAAC) is a lightweight construction material that was used in the construction of some public buildings like schools and hospitals between the 1950s and 1990s. It was used mostly in flat roofing, but also in some pitched roofs, floors and walls.

It was quicker to produce, easier to install, and cheaper than standard concrete. Despite its name, it is very different to traditional concrete although it looks similar. It is aerated, or ‘bubbly’, and is therefore less durable than traditional concrete.

Why is there a risk?

RAAC can be susceptible to failure when exposed to moisture. The ‘bubbles’ can allow water to enter the material. This moisture can also cause decay in any reinforcement steel (‘rebar’) present in the material.

In February 2022, a report was published by The Institution of Structural Engineers RAAC Group following an incident in England in 2018 and an initial safety alert in 2019. Guidance was published by the group in April 2023.

What steps has the council taken?

Following the publication of The Institution’s guidance, the council proactively engaged the services of an external specialist structural engineer to survey the council’s properties. To date, more than 400 properties have been surveyed covering schools, corporate buildings and community facilities. All schools have been inspected, with surveys of a very small number of other buildings to be completed in the coming weeks. RAAC was identified in four: Ravenswood Primary School in Cumbernauld, the extension at Caldervale High School in Airdrie, Pivot Community Facility in Moodiesburn and Motherwell Concert Hall and Theatre. 

In Ravenswood Primary School, remedial action has already been taken to ensure safety. This has included the installation of permanent steel supports and other measures as appropriate. The structural engineers have advised us that there are no immediate safety concerns and regular surveys will continue in the meantime.

While remedial action had previously been carried out at the Pivot Community Facility in Moodiesburn, during the most recent inspection by external specialists it was identified there has been potential deterioration of areas of RAAC in the centre, including to the reinforcement steel contained within the RAAC planks. We have decided to immediately close the Pivot Centre to all activity for the foreseeable future on safety grounds.

Staff will be in touch with groups and people who had bookings for the centre to help them secure alternative provision. There is no RAAC present in the library and this will remain open. However, this will remain under review depending on what access may be required for any works or maintenance.

A small amount of RAAC has been identified in an area of the extension to the rear of Caldervale High School. This separate extension is not used by pupils or staff and a further intrusive survey is being carried out to assess the condition. This will not have any impact on school operations. 

As a precautionary measure, a further assessment has already been carried out on the main building of the school which confirms that RAAC is not present.

An initial survey has been carried out on the Motherwell Concert Hall and Theatre which has found that the majority of the roof contains RAAC. The inspection has also found evidence of water ingress to the roof space and a full intrusive survey has been carried out. The concert hall and theatre remains closed to staff and visitors with immediate effect and all scheduled shows and events have been cancelled indefinitely. 

We are working with promoters to relocate other shows to another venue and will be in contact with ticket holders with
full details.

Ticket holder information can be found here

The civic centre which is part of the complex remains open. A survey was carried on both the civic centre and civic square buildings and no evidence of RAAC was found.

What happens next?

Permanent solutions for the schools and community centre are being designed with a view to works being undertaken in 2024.

As outlined above, a full intrusive survey has been carried out at Motherwell Concert Hall and Theatre and both venues are closed with immediate effect until further notice. While this is disappointing, the safety of staff and visitors to the concert hall and theatre is a priority.

The work to inspect Motherwell Concert Hall and Theatre is complete and we anticipate a full structural report for detailed consideration by the relevant technical officers which will lead to a report to council. 

To provide certainty for acts and audiences, we have taken the regrettable decision to cancel all performances in the concert hall and theatre indefinitely and we are working with promoters to relocate other shows to another venue. 

Ticketholders will be contacted directly by the team at the concert hall and theatre regarding shows and events. 

This year's pantomime, Jack and the Beanstalk, will now take place at Ravenscraig Regional Sports Facility and all ticket holders will be emailed with full details. 

As is normal practice, our regular survey works continue across the remaining estate and will be part of an annual monitoring inspection by independent engineers.

While all pertinent professional guidance has been followed to date, we will continue to ensure we comply with any further guidance coming from government or relevant professional bodies.

Is council housing affected?

An initial desktop analysis identified that up to 400 properties could potentially have RAAC as part of their construction. A further more detailed analysis has revealed the figure to be up to 167 properties which may have had RAAC used as part of their construction. This assessment is ongoing and includes inspections and checks with our appointed independent specialist surveyors and structural engineers. We will liaise directly with tenants if any remedial works are required.

Are private and commercial buildings affected?

The Institution of Structural Engineers advises that if an owner or manager has a building or property constructed between the mid-1950s and mid-1990s and is unsure of the form of construction, they should carry out an inspection and a risk assessment. This will help to identify or eliminate the possibility of RAAC within the fabric where necessary. 

If RAAC planks are present, their structural condition will need to be determined by a Chartered or Incorporated Structural Engineer. 

Subject to the Chartered or Incorporated Structural Engineer’s findings, a process of ongoing monitoring and/or remedial propping or strengthening works may be needed. In some instances, it may be necessary to remove or replace RAAC planks

Further information can be found on its website

Page last updated:
10 Apr 2024

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