Five fire engines are in attendance and crews wearing breathing apparatus are working to extinguish the flames using hose reel jets and main jets.
There are reports that the roof may contain asbestos that has ben released into the air
No injuries have been reported.
A spokesman for Kent Fire and Rescue said :
Five fire engines remain in attendance at the scene of a fire involving multiple outbuildings in Leysdown Road, in Leysdown-on-Sea, Sheerness, where crews are making steady progress.
People living or working in the immediate area are still advised to close windows and doors as a precaution due to the smoke coming from the incident.
No injuries have been reported.
A police spokesman added: “Kent Police was called by Kent Fire and Rescue Service at 11.36 am to a fire at a property in Leysdown Road, Leysdown-on-Sea.
“Officers are currently at the scene and have closed the road to assist fire crews tackle the blaze.”