Raac concrete found at Heathrow and Gatwick airports

Aviation authorities are carrying out checks on the collapse-prone building material

The airports have confirmed the presence of the concrete (PA Archive)

Collapse-prone concrete is present in buildings at Britain's two busiest airports, aviation authorities have confirmed.

Heathrow and Gatwick on Friday afternoon both revealed that that they have been carrying out structural inspections on the material.

Heathrow, which handled 62 million passengers last year, said it was taking "remedial steps" to ensure safety and working on a long-term plan to ensure safety.

And Gatwick, which flew an estimated 33 million in 2022, said it was keeping a register of buildings containing Raac and that its regular inspections had turned up no concerns.

Reinforced autoclaved aerated concrete or Raac is a lightweight alternative to standard concrete that was used mostly in flat roofing but also in floors and walls across buildings during the 1950s to 1990s.

But in the past few years, Raac has failed in a number of settings – collapsing without warning.

This has prompted schools, hospitals and other public buildings to take urgent action where it is present.

A spokesperson for Heathrow said: “Industry has been aware and acting on the remedial steps that should be taken in buildings that contain this material. Passenger and colleague safety will always be our first priority. We will continue to update stakeholders across the sector as our plans for permanent solutions progress.”

And a Gatwick spokesperson said: “We have a register of locations containing Raac on the airport campus, which are closely monitored through a regular comprehensive structural inspection regime. Our most recent inspection in June 2023 did not present any concerns and we will continue to monitor on a regular basis.”