Reinforced autoclaved aerated concrete (RAAC) - request for information
Dear colleague
Reinforced autoclaved aerated concrete (RAAC) - request for information
We are working with the Scottish Government to help in the dissemination of information on the risks arising from the presence of RAAC in buildings and to gather better information on its presence in domestic buildings. Data is being gathered across the public sector in Scotland to understand the extent of the issue.
RAAC is a lightweight structural construction material used between the 1950s and 1990s in the floors, walls and roofs of some buildings in Scotland, including some residential properties. It is no longer used in buildings in Scotland. While it is likely that RAAC is not widespread in homes provided by social landlords, several landlords have identified the presence of RAAC in some of the homes they provide. The age of the property and its construction type are good initial indicators of the potential for RAAC to be present, although it may be in other homes where original building components have been replaced, for example where flat roofs have been replaced during the time when RAAC was in use. Collaborative Reporting for Safer Structures (CROSS-UK) provides more information on its RAAC theme page. Information is also available on the Institution of Structural Engineers (IStructE) website.
The presence of RAAC does not necessarily present an immediate risk. However, the safety of tenants and residents is of paramount importance, and so it is critical that landlords have a good understanding of the presence and condition of RAAC in the homes they provide and that they have an appropriate plan for its management. This good understanding is also important to enable landlords to communicate effectively with their tenants to provide appropriate reassurance and information about any action that the landlord may need to take.
We are aware that some landlords are well-advanced in their work to identify and manage the risks around RAAC. For those that have yet to begin this work, or are in the early stages, the Scottish Government is advising social landlords to take a four-stage escalation approach to the identification and risk management of RAAC in their homes:
Stage 1: Discovery – establish presence of RAAC through desk-based review
Stage 2: Discovery – verify presence of RAAC through visual inspection
Stage 3: Assessment – detailed site survey to identify risk and response
Stage 4: Implement RAAC Risk Management.
We set out more information on each of these stages in Annex A. The Institution of Structural Engineers (IStructE) provides detailed guidance on the investigation and assessment of RAAC on its website. Landlords should seek suitably qualified advisors where necessary.
Landlords will also need to consider their responsibilities in the role as the factor of homes with RAAC and should consider the potential for the presence of RAAC in non-housing buildings they own or manage.
As a first step to establish the extent of RAAC in social housing in Scotland we ask that you provide us with the following information:
- Is RAAC present in any of the homes you provide to tenants?
- If you have answered yes, how many homes are affected?
- If you have answered currently investigating, how many homes may have RAAC present?
Where you have identified that RAAC is present or may be present in common areas, include the number of affected homes in the figures at data return columns 2 and 3 respectively. Please use the comments feature to tell us about any information you have about:
- homes that have or may have RAAC and which you do not own but have maintenance obligations for;
- homes which you factor that have or may have RAAC;
- homes which you have previously sold which have or may have RAAC; and
- non-domestic properties you own or manage that have RAAC.
Please download the RAAC return here and then once complete, upload to the Documents area of the Social Landlord Portal.
(Portal access will be required for upload, please speak to your Portal administrator if you require access.)
Please provide this information by the end of 31 October 2023. Please let us know if you will not be able to provide us with the information by that date, and we can discuss options for submitting the information.
We will contact you for further information where you have identified RAAC in your homes or that there is the potential of RAAC being in your homes. This further data collection will be to provide more information on numbers involved, the assessment of risk and mitigation or remedial action required.
If in your return you indicate that RAAC is not present in any of your homes, but you subsequently identify that it is, please inform us immediately.
We will use this information to help provide a clear national assessment of RAAC in social housing in Scotland and to assist in the development of an appropriate policy response.
Yours sincerely
Michael Cameron
Chief Executive
Annex A: Stages of action – RAAC risk assessment and management
Stage 1 Discovery – establish presence of RAAC through desk-based review
A. Check drawings and specifications from the time of construction or subsequent works, photographs from site dating back to construction or during maintenance works. Where possible seek input from building professionals and estates teams who have worked on the building.
B. If the building owner is satisfied that there is no evidence of RAAC on:
- building records, and
- construction period (including extensions and conversion work) does not fit the risk profile of RAAC, and
- there are no other relevant criteria,
and that visual survey is not necessary then the process can be exited. Record evidence and decision making for future reference.
C. Stage 1 can be undertaken by an appointed chartered engineer, surveyor construction consultant, or where relevant by a suitably qualified in-house construction professional.
Stage 2 Discovery – verify presence of RAAC through visual inspection
A. Involving visiting the site and confirming its presence or not.
B. If there is no evidence of RAAC then the process can be exited. Record evidence and decision making for future reference.
C. If RAAC is identified, or there is still uncertainty, then a detailed site survey (Stage 3) should be undertaken.
D. Stage 2 can be undertaken by an appointed chartered engineer, surveyor construction consultant or where relevant by a suitably qualified in-house construction professional.
Stage 3 Assessment – Detailed site survey to identify risk and response
A. All information gathered to date should be provided to the appointed chartered engineer or surveyor. Where necessary they may carry out further desk study or visual inspection.
B. A plan should be prepared to carry out the work, including access requirements and the extent of sampling necessary.
C. Information on survey, risk factors, assessment of risk, and remediation or management of risk are set out in the April 2023 IStructE document ‘Reinforced Autoclaved Aerated Concrete (RAAC) Investigation and Assessment – Further Guidance’.
D. Assess the risk in accordance with the IStructE guidance.
E. This stage should be undertaken by a qualified chartered engineer or chartered building surveyor with experience of RAAC using the published IStructE guidance.
F. The findings and conclusions on risks should be fully reported and provided to the building owner or party commissioning the work.
Stage 4 – Implement RAAC Risk Management
A. Deliver actions to manage the risk set out by the construction professional, this covers:
- Immediate or short-term actions including physical mitigation such as propping the roof and closing parts of buildings.
- Longer-term actions, may include a monitoring programme; long term physical mitigation; or remediation and removal of the risk through replacement of the structural element (which in some cases may be achieved through a broader programme of building replacement).
B. Commission work through contractors; set in place an action plan for monitoring as required.