Concerned about crumbling concrete?

Posted: 2 November 2023

Reinforced Autoclaved Aerated Concrete (RAAC) has made the headlines recently for all the wrong reasons. This is due to concerns about the risk of sudden collapse in schools and other buildings where the material is used.

RAAC is a lightweight form of concrete, commonly used in construction between the 1950s and mid-1990s. It’s predominantly found in precast panels in roofs (commonly flat roofs, but sometimes pitched) and occasionally in floors and walls.

RAAC has been a widely used building material because it’s cheap, lightweight and provides good thermal insulation. RAAC panels are typically light grey or white in appearance, and the underside of the panels will generally appear smooth. Inside the panels are bubbly, bearing some resemblance to an aerated chocolate bar.

raac concrete close-up
Inside an RAAC panel (example)

Unfortunately RAAC’s lightweight properties come at a cost to its structural strength. Due to its highly porous nature, it is significantly more prone to cracks and weaknesses.

RAAC is present in some buildings despite it being well over its expected lifespan of 30 years. Roofs built with RAAC have been known to collapse suddenly, including cases where the panels appeared to be in good condition.

In late 2018, the Local Government Association (LGA) and the Department for Education (DfE) contacted all school building owners to draw attention to a recent failure involving a flat roof constructed using RAAC panels.

In May 2019 the Standing Committee on Structural Safety (SCOSS) issued an alert to highlight the potential risks from RAAC.

Since then, sudden collapses in RAAC panels in roofs continue to be reported. Guidance was issued by the Department for Education, requiring responsible bodies within the education sector to identify RAAC in their estates.

Whilst the recent news coverage focuses on RAAC in schools, the scale of its use is much wider and across both the public and private sector. RAAC has been identified in hospitals, theatres, airports, residential buildings, universities, shopping centres, police stations and court buildings.

Due to the limited durability and known issues, it is essential that building owners and/or the responsible persons take steps to confirm the safety of any RAAC in their premises. 

If RAAC is identified or suspected, guidance should be sought from an appropriately qualified building surveyor or structural engineer with experience of RAAC.

The initial task of the surveyor or engineer is to confirm if RAAC is present in the premises, subsequently determining its condition and required remedial action, which may include replacement.

As Allianz policies contain a standard market exclusion in respect of Buildings, where there is destruction or damage to any building or structure caused by its own collapse or cracking, it is important that professional guidance is sought to address any issues associated with the presence of RAAC.

Wherever RAAC has been identified, customers should contact their broker for guidance and to fulfil a duty to disclose material information.

To ensure that the building surveyor and/or structural engineer has the appropriate qualifications and experience, the government guidance suggests the following credentials:

Building surveyor

  • relevant degree e.g., BSc (Hons) Building Surveying
  • 3 years relevant experience assessing building condition, this can be measured in the time elapsed since completion of an appropriate industry related degree or qualification, e.g. BSc (Hons) Building Surveying
  • evidence of one-year minimum relevant RAAC project / commission experience
  • membership of Royal Institution of Chartered Surveyors with Building Surveyor designation (not essential).

Structural engineer

  • Chartered Membership of the Institution of Structural Engineers (CEng MIStructE), and/or
  • Chartered Membership of the Institution of Civil Engineers (CEng MICE).

Evidence of experience of the following:

  • surveying, assessment and design/specification of remediation works to existing buildings
  • visual inspection works and desk-study works
  • physical inspection works, either specification and management or physical works
  • management and post-completion evaluation of remedial works construction
  • RAAC experience is essential.
More guidance on appointing an appropriately qualified building surveyor or structural engineer can be found at - Reinforced Autoclaved Aerated Concrete (RAAC): Identification guidance.

Where remedial action is needed, we’re usually able to offer existing Allianz customers a Contract Works policy to cover the additional building works – these types of covers neatly complement an existing Allianz policy which continues to cover the buildings.

If as a result of remediation or repair works, any buildings are going to be unoccupied and not in active use by a customer or their tenants for more than 30 consecutive days, customers should notify their broker.

Any concerns or queries about the extent of cover can also be discussed with their broker.

It’s important to recognise that some of the challenges associated with RAAC and other concrete variants such as Autoclaved Aerated Concrete (AAC) and High Alumina Cement (HAC) are not new.

If an organisation has questions or doubts relating to the performance of any materials used in the construction of its premises or buildings, guidance from an appropriately qualified building surveyor and structural engineer is clearly critical.

men on construction site

It’s also worth highlighting the potential for investigation, assessment, and remediation work relating to RAAC to present an increased exposure to asbestos, given that they may both be present in the same areas.

It’s key that the dangers posed by asbestos and asbestos containing materials are appropriately assessed in accordance with Health and Safety Executive (HSE) guidance and the requirements of the Control of Asbestos Regulations 2012.

The information contained in this press release relates to Allianz Insurance plc. Allianz Insurance plc is one of the largest general insurers in the UK and part of the Allianz Group.

About Allianz Holdings plc

Allianz Holdings plc is the non-regulated holding company which owns the principal insurance operations of Allianz SE in Great Britain.

About Allianz

The Allianz Group is one of the world's leading insurers and asset managers with more than 100 million* private and corporate customers in more than 70 countries. Allianz customers benefit from a broad range of personal and corporate insurance services, ranging from property, life and health insurance to assistance services to credit insurance and global business insurance. Allianz is one of the world’s largest investors, managing 790 billion euros on behalf of its insurance customers. Furthermore, our asset managers PIMCO and Allianz Global Investors manage 1.7 trillion euros of third-party assets. Thanks to our systematic integration of ecological and social criteria in our business processes and investment decisions, we are amongst the leaders in the insurance industry in the Dow Jones Sustainability Index. In 2021, over 150,000 employees achieved total revenues of 148.5 billion euros and an operating profit of 13.4 billion euros for the group.

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