News Topic: Between  a RAAC and a Hard Place

By Rhiannon Cooper, Membership and Communications Coordinator - 6th September 2023

I am sure, given current extensive media coverage, you will be aware of the dreaded building material, ‘Reinforced Autoclaved Aerated Concrete’ or  RAAC.

It might be that you have children who have had to resume online learning reminiscent of the Covid19 pandemic, or it might be because your industry sector is directly impacted. Whatever the reason, by now you will be aware of the issues and the controversy surrounding this low cost, lightweight and easy to install material.  

It was used for a huge proportion of municipal development and construction through the 1950s into the 80s and found in buildings constructed as late as the 90s. Given the short lifespan of RAAC, it is no surprise that issues are starting to arise, and the cracks (literally, in some cases) are starting to show.

Politically, the focus has been on educational buildings, with more than 100 schools being impacted, but the issue of RAAC is not limited to the education sector.  Many other at risk buildings have been identified across the wider public estate. 

There have been multiple hospitals identified, various court buildings and even some residential homes have made the list, so it got me thinking about the nature of our sector.

Are your premises free of RAAC?

If RAAC is present, is it in good condition?

Fortunately (a silver lining perhaps…?) RAAC has a characteristic appearance that sets it apart from regular high density concrete.  A simple, visual inspection will suffice (The Government has produced a RAAC guide linked below), checking for:

  • Aerated structures; RAAC is porous.  
  • Cellular or honeycomb like appearance, seen when the material is cut or broken. 
  • Textured surface; check for visible pores/holes. 

We would like hear from you if you have been affected and hear your plans to address the problem.


Whilst PARN cannot offer any direct support, it may be useful for us to compile a register of actions being taken and any on-going monitoring being put in place. In this way we can provide a network and a community that will allow sharing of solutions and hopefully direct future actions to mitigate the problem.

Please reach out and let me know what this means for you; we are looking to create conversations amongst the network and even if you just want to share your thoughts, I would love to hear from you. 

Email me here

Link to the Government RAAC Guidance: click here

Link to the list of IStructE Chartered & Incorporated-Members who have experience of RAAC: click here