Kent Fire and Rescue Service (KFRS) was called to a fire in a section of a museum in East Crosswall, The Royal Harbour in Ramsgate just before 5.00pm on Tuesday 23 November.
Four fire engines arrived and crews wearing breathing apparatus put the fire out using a fog spike and hose reel jets, preventing further fire spread and reducing smoke damage.
Fire crews have praised museum staff for having closed internal doors, which protected other sections of the building.
There were no reported injuries.
Kent Fire and Rescue Service has said the fire is believed to have been started deliberately.