Both airports said they were aware of having reinforced autoclaved aerated concrete some time ago and said that steps were taken to remedy it.
Concerns have been raised about RAAC because it has an aerated, bubbly texture which is cheaper to produce than traditional concrete, but it only has an expected lifespan of around 30 years and can be prone to collapse after that.
It was used from the mid 1950s to the mid 1990s in many public buildings, including many schools.
The concrete was first found at Heathrow’s Terminal Three last year, prompting temporary remedies.
In a statement, the airport said: “Industry has been aware and acting on the remedial steps that should be taken in buildings that contain this material.
“We, like many others, have been assessing our estate and will continue to mitigate the risk where this material is found.
“Passenger and colleague safety will always be our first priority, and we will continue to update stakeholders across the sector as our plans for permanent solutions progress."
A Gatwick spokesperson also confirmed that RAAC was found on its premises, but stressed there was no risk to passengers.
“We have a register of locations containing RAAC on the airport campus, which are closely monitored through a regular comprehensive structural inspection regime,” said the spokesperson.
“Our most recent inspection in June 2023 did not present any concerns, and we will continue to monitor on a regular basis."
The issue was catapulted to the top of the political agenda last week after more than 100 schools, colleges, and nurseries across England were ordered to close buildings over the material.
The Department for Education has revealed that a total of 147 schools have been affected by the crumbling concrete, including more than 10 London schools.
Schools minister Nick Gibb said the collapse of a beam that had been considered safe over the summer sparked an urgent rethink on whether buildings with the concrete could remain open.
Further controversy was sparked after Education Secretary Gillian Keegan was criticised for questioning why no-one says “you’ve done a f****** good job” while “everyone else has sat on their arse and done nothing” over the concrete.