Reinforced Autoclaved Aerated Concrete (RAAC) is a lightweight building material that was commonly used in the UK construction industry from the mid-20th century until the mid-1990s. It was often incorporated into the construction of public buildings, such as schools and hospitals.

RAAC is distinct from traditional concrete in its structure. It is aerated, meaning it contains tiny air pockets that make it lighter and easier to work with. However, this also makes it less durable. RAAC contains no aggregate, unlike common concrete. RAAC was typically used to form roof planks, wall panels, and sometimes floor planks in the UK from the mid-1950s to the mid-1990s.

Key differences from traditional concrete:

• Lightweight and porous: RAAC contains tiny air pockets, making it lighter and easier to work with than traditional concrete. However, this also makes it less durable.

• No aggregate: Unlike traditional concrete, RAAC does not contain any aggregate (such as gravel or sand).

While RAAC offered advantages in terms of speed of production, installation, and cost, its susceptibility to deterioration has led to concerns about its use in critical structures.

The Institute of Structural Engineers issued updated guidance in 2023 on how to investigate and assess existing RAAC panels. RAAC has demonstrated lower durability compared to other concrete building materials. Unlike traditional concrete, RAAC's manufacturing process results in a significantly weaker material. The expected lifespan of RAAC panels is typically around 30 years, but proper building maintenance can extend this. RAAC panels may be more susceptible to failure due to water damage, issues during the original production process, or incorrect installation techniques.

It is important to understand that RAAC itself does not present a health hazard. The primary concern with RAAC relates to its structural stability and the potential for it to deteriorate over time.

RAAC is susceptible to damage from moisture. Due to its porous nature, water can easily penetrate the material, potentially causing the steel reinforcement within to corrode. In rare and severe cases, this can lead to unexpected structural failure.

Recognising the potential risks, the Institute of Structural Engineers RAAC Group released a comprehensive report in February 2022, followed by further guidance in April 2023. These reports provide valuable information for building owners and professionals on identifying, assessing, and mitigating the hazards associated with RAAC.

To better understand the prevalence of RAAC in domestic buildings, the Scottish Housing Regulator, in collaboration with the Scottish Government, requires registered social landlords such as Bridgewater Housing Association to report properties which have been confirmed to contain RAAC and also any other properties which are under investigation.

While the presence of RAAC may be a concern, it does not automatically mean a building is unsafe. However, neglecting maintenance or allowing moisture ingress can significantly accelerate deterioration in RAAC panels, potentially leading to warping, deflection, and increased risk of failure.

Bridgewater HA has undertaken a comprehensive programme of surveys and inspections to identify properties within our housing stock (both the houses that we own and the private houses where we act as property factor) that may contain RAAC. These inspections include both visual assessments and more in-depth surveys to thoroughly evaluate the presence, distribution, and condition of any RAAC.

We are currently working closely with independent structural engineers to develop appropriate plans for ensuring the continued structural integrity of all affected properties.

The safety and well-being of our tenants is our main concern. We are committed to taking all necessary steps to maintain a safe living environment for all residents.

RAAC has been identified in 16 blocks located on 4 Streets.

The presence of RAAC has been confirmed in the roof structures and communal areas of these blocks. All affected properties are residential buildings.

We want to emphasise that, based on the initial findings of our engineers, there is no immediate risk to the structural integrity of the vast majority of buildings surveyed at this time. We've identified one individual property where some remedial work may be needed, and we've already taken appropriate precautionary measures with the residents concearned.

Bridgewater HA is actively working with independent structural engineers to identify all affected properties and determine the necessary steps to ensure their structural integrity.

Qualified engineers will assess the structural condition of each property. These assessments, along with detailed risk analyses, will guide the development of a management plan. This plan will determine whether the replacement of any RAAC components is necessary and, if so, when.

If the assessments indicate that the existing RAAC panels can be retained, ongoing monitoring will be crucial to detect any future signs of deterioration.

Our Commitment to Resident Safety:

The safety and well-being of our tenants and residents is our top priority. We are committed to taking all necessary measures to ensure the continued safety of all residents.

Keeping You Informed:

We will continue to conduct thorough surveys to determine the full extent of RAAC within our housing stock. Tenants and residents of all known affected blocks have been informed, but further surveys are under way and if any further blocks are identified as containing RAAC we will communicate this to the tenants/residents in those blocks.

We will provide regular updates on our progress and communicate any necessary actions to affected residents.

Dedicated Points of Contact:

The Association’s Customer Services team is available to assist with all enquiries and will ensure they are directed to our Head of Property Services, Steven Ferrie to be answered, normally within 2 working days. We will continue to engage with all affected customers as more information becomes available throughout the survey process.

Although no programme for works has yet been identified/agreed, the duration of any remediation work will vary significantly depending on the specific building, the extent of the RAAC and the specific remedial action required. Due to the unique nature of each property, it is impossible to provide a precise timeframe for remediation at this stage. In some cases, such as the removal of a RAAC flat roof, tenants or other residents may need to temporarily vacate their homes during the construction work.

We understand that this uncertainty can be concerning. We will work closely with affected tenants and other residents to minimise disruption and provide as much advance notice as possible regarding any necessary relocations.

Bridgewater HA does not have any responsibility for the maintenance or repair of privately owned properties. Property owners are solely responsible for the upkeep of their own homes. Therefore, we have no obligation to identify or repair RAAC within privately owned properties. We are committed to advsing owners in neighbouring properties where RAAC has been identified where appropraite.

However, in situations where privately owned properties are located within blocks where RAAC has been identified in communal areas, the Association, in its role as Factor, will work with property owners to try to ensure necessary monitoring and remedial works are carried out. In our role as property factor, we arrange for the maintenance and repair of common parts of blocks which contain a mix of flats which are privately owned or which are owned by the Association, but it remains the responsibility of the owners of the individual flats to pay for their share of the cost of carrying out any necessary work.

If you are a private owner and have received a letter from us advising we have identified RAAC in common areas or neighbouring properties within your block or are concerned that your home may contain RAAC, we recommend that you have it inspected by a qualified Chartered Structural Engineer in accordance with the guidance issued by the Scottish Government and the Institution of Structural Engineers. The chartered Structural Engineer will be able to assess the condition of the concrete planks, whether RAAC is present, and advise you on any necessary mitigation works.

In the meantime, there are a few things that you can do to make your home safer:

• Check for any signs of damage to the RAAC planks, such as cracks, bulges, or discolouration (see images below). If you see any damage, contact a qualified chartered Surveyor/Structural Engineer immediately. You should not undertake remedial action yourself.

It is important to take independent advice on the potential risks to you and to have your home inspected by a qualified Structural Engineer if you are in any way concerned.

While the Association cannot provide you with property, legal or financial advice, you can find contact details for suitably qualified professionals via the RICS Website or via the Institution of Structural Engineers website.

Renfrewshire Council’s scheme of assistance aims to provide homeowners with information and guidance to help them effectively maintain and repair their own properties.

Surveys have been conducted in various locations across our stock in Erskine. If RAAC has been identified we will have notified you in writing.

Visual surveys have been conducted by Structural Engineers and disruptive surveys are now being planned in identified properties initially to ascertain the location and extent of RAAC in these properties.

We understand that construction work on tenant properties can potentially impact neighbouring owner-occupied homes. Where RAAC is situated within the common parts of a block, then both the Association and private owners within the block have an interest in the common parts which need to be remediated.

To minimise any disruption, we plan to conduct pilot projects before commencing larger-scale remedial works. These pilot projects will help us identify and address any potential disruptions to neighbouring properties. This proactive approach will ensure that we can effectively mitigate any potential inconveniences for our neighbours during the remediation process.

The Association has checked our stock and can confirm that to date only the streets where we have written to residents are affected. We have written to all customers to confirm their home is affected. If you have not received a letter about RAAC you should not be impacted by this issue. All letters will be issued by Spring 2025 as the surveys are completed.