RAAC, and the buildings that still contain it

Reinforced autoclaved aerated concrete, RAAC, is a lightweight form of concrete that was cheap to make and quick to lay. It was used across the UK from the mid 1950s to the mid 1990s, mostly in flat roof panels but also in some floors and walls. The problem is not the material in the abstract. It is that RAAC was given a design life of around 30 years, and the buildings that contain it were mostly put up between 1950 and 1990. Nearly all of it is now beyond the life it was designed for.

Why it matters

Unlike ordinary reinforced concrete, RAAC has little reserve of strength once it starts to deteriorate. Water gets in, the reinforcement corrodes, and the panels can fail with little visible warning. The Building Research Establishment flagged this as far back as 1996, warning of excessive deflection and cracking in RAAC roof planks. What changed the public picture was 2023, when a number of schools were told to close spaces at short notice days before the autumn term.

The counts that followed give a sense of the scale. In England, the Department for Education has confirmed RAAC in 237 schools and colleges, and by September 2025 had permanently removed it from 62 of them, working to a 2029 deadline for the rest through rebuilding or replacement. In the NHS, seven hospitals built predominantly from RAAC are being replaced through the New Hospital Programme, alongside removal work across many individual buildings.

Schools and hospitals were surveyed because someone made them a priority. The material itself did not confine itself to those two sectors. It sits in offices, leisure centres, retail units, libraries and older commercial premises put up in the same decades, many of which have never been checked.

The duty sits with the building manager

There is no single RAAC statute. The obligation comes through the ordinary duties that already apply to whoever controls a building: to assess the risks, to keep the structure safe for the people who use it, and under the Health and Safety at Work etc. Act 1974 and the workplace regulations to manage foreseeable structural risk. For a building of the right age, RAAC is a foreseeable risk, and inspecting for it is part of managing it.

That means the first task is knowing whether it is even present. A visual check by someone competent, informed by the original construction date and the type of roof, is the starting point. Where RAAC is confirmed, the panels need a condition assessment, a record of where they are and what state they are in, and a review schedule so a slow decline is caught rather than discovered.

What a good record looks like

The failure mode is rarely that a manager decided RAAC was acceptable. It is that nobody knew it was there, or the survey that identified it a few years ago cannot now be found, or the last inspection date has been lost. A material like this rewards the same discipline as any other building risk: name it, locate it, record its condition, and diarise the next look.

That is where materials records earn their place. SAMRISK holds a materials register alongside the building's risk assessments and the documents that evidence them, each versioned and dated, so the survey you are relying on is the current one rather than a PDF in an old inbox. The compliance calendar carries the review dates and chains them, so a panel due another inspection surfaces before the date passes rather than after.

RAAC is a reminder that a building is only as safe as the record of what it is made of. The material will keep ageing whether or not anyone is watching it. For any building of the right vintage, the useful question is narrow: do you know if it is there, and when someone last looked.