Medway Council’s headquarters has been closed after RAAC was found in its roof.

Gun Wharf has been entirely closed due to concerns about the reinforced autoclaved aerated concrete which may mean the building is potentially unsafe.

It will remain closed until Friday at least for tests to be carried out and the scale of the problem to be understood.

The building holds most of the council’s operations, as well as the county and family courts for the Towns.

RAAC is a form of lightweight concrete used in construction in many buildings between the 1950s and 1990s which has recently been found to be structurally unsound.

It is a cheaper, quicker and easier to install alternative to typical concrete but the air bubbles inside the concrete make it susceptible to structural failure when exposed to moisture.

In September, more than 100 schools across the UK were closed due to safety concerns regarding the material and many more buildings were also affected.

It is unclear to what extent Gun Wharf is affected by RAAC or how imminent the possible danger is, however, the entire building has been closed as a precautionary measure.

Council leader Cllr Vince Maple said: “It is regrettable we have had to temporarily close our main offices in Chatham.

“Initial specialist surveys have found reinforced autoclaved aerated concrete (RAAC) in some parts of the roof. Unfortunately, these initial assessments of accessible areas also revealed some damage.

“Gun Wharf will therefore remain closed for at least the rest of this week for the safety of all our staff and residents, and to allow further structural tests to be carried out to fully assess the extent of the damage.

“We are not alone in finding ourselves in this unfortunate position, with other councils and public buildings, such as hospitals and theatres, across Kent and the rest of the country working through the unknowns of rectifying this type of concrete being used in older buildings.”

However, Cllr Maple said council operations would continue as usual, despite the issue, and residents would still receive access to all council services.

He continued: “Since the pandemic, plans are in place which enable our staff to work off-site and continue providing high-quality support to our most vulnerable residents. Members of the public can also access support through our online forms by visiting our website or some services in person at our libraries across Medway.”