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.
RAAC can be susceptible to failure especially 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 Institute 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.
Public authorities throughout the UK established a programme of surveys, including this Council, to be carried out on its portfolio of properties, including housing stock, to ascertain whether any of these properties contain RAAC and its condition.
A report was submitted to Council on Thursday 30 November 2023.
The approach to surveying for RAAC in public buildings identified that the buildings be split into three priority areas to minimise and control risk:
Priority One: Primary schools and secondary schools
Desktop study and visual inspections for RAAC within schools across Clackmannanshire have been carried out. A total number of seven schools were identified for further investigations by the specialist structural engineer. The Council’s building engineer confirmed there was no RAAC present within these buildings.
Priority Two: Social work settings including care homes
The Council’s desktop study took place during autumn/winter 2023 and no properties were identified as containing RAAC.
Priority Three: Depots, offices and all other civic/commercial estate
The desktop study confirmed one public building (Speirs Centre) to contain RAAC. This building is being managed and monitored on a 6 monthly basis by a structural engineer.
After a desktop study of our flats, our focus has been on surveying low to mid rise buildings.
Residents living in flats in Chapelle Crescent, Tillicoultry, were sent letters to inform them of the Council’s planning survey programme which took place between 25 September 2023 and 6 October 2023.
Residents in other areas were lettered during week commencing Monday 9 October about the survey programme.
The surveys by the Council’s building engineer were completed on Friday 20 October, with 49 blocks (containing a total 445 flats) surveyed for the presence of RAAC within the roof structures of buildings.
The Council’s building engineer confirmed as a result of these inspections that RAAC was present in the roof structure of three buildings (containing 30 flats).
The Council’s building standards officer also attended the three buildings and agreed with the Council’s building engineer on the condition of the roof structures.
With the buildings being dangerous and risk of collapse the Council had a legal obligation to evacuate residents from these three buildings. The legal basis for the evacuation was in terms of Section 42 of the Building (Scotland) Act 2003 which was served on residents. A Dangerous Building Notice in terms of Sections 29 and 30 of this Act was also served on owners which required the owners to obtain their own structural report.
The survey programme has identified a further seven blocks (containing 72 flats) where RAAC is present, but there is no immediate concern noted over the condition and these blocks are being managed and monitored.
The Council did not take the decision to evacuate residents from their homes lightly and understands how difficult and upsetting this was. However, based on the information that was provided by the Council’s building engineer the concern was to preserve lives.
Some owners and Council tenants of those buildings that were evacuated were provided accommodation within hotels nearby or were able to stay with family or friends. Other assistance was offered in line with our statutory obligations.
Further advice can be sought from Citizens Advice Scotland or Shelter Scotland.
At the present time the three evacuated blocks in Tillicoultry remain unoccupied, due to the statutory notice served by Building Standards on the owners of the properties.
Regular visual inspection of the three evacuated blocks is ongoing to ensure continuous monitoring of condition with both the Council and owners keen to see movement towards a decision made with respect of the evacuated blocks.
Since January 2025, officers have been engaging with the owners and the Council’s contractors over the potential options available. The Council’s current roof and render contractor has relevant experience in respect of RAAC remediation in public buildings in England. On the basis of this experience, our contractor costed proposals for the three evacuated blocks.
Officers have been engaging with the owners to discuss the options to proceed with remedials, which would require them to contribute to the associated costs or consider a voluntary sale to the Council.
Agreement has now been made with the owners of the High Street block for remedials and we are currently progressing the legal process of this agreement. This has enabled the Council to initiate the process involved in the planned improvement works to the block which includes a fully certified structural engineer design and drawing of the suitable roof replacement including full RAAC removal. The contractor will begin work early 2026.
Discussions are ongoing with the owners of the remaining 2 blocks.
The seven RAAC managed and monitored blocks, which remain occupied, continue to be inspected on a regular basis. More invasive surveys are required of the RAAC panels which would involve hatches being cut in the ceilings of the top floor properties. Further guidance has been obtained, and we will be contacting the owners and occupiers in these blocks in due course. This work will provide officers with information in order to establish a forward plan of action for these occupied blocks in line with the wider stock asset evaluation.
The Institution of Structural Engineering advises that any private owner with properties constructed between the mid-1950s and mid-1990s should conduct a survey of the building to identify or eliminate the possibility of RAAC within the fabric where necessary and assess whether remedial work is required.
Housing Options Team
Kilncraigs, Greenside Street, Alloa, FK10 1EB
Tel: 01259 225122
Email: home@clacks.gov.uk