Firefighters from Whitchurch, Andover, Winchester, Basingstoke, Stockbridge, Eastleigh and Tadley along with crews from Royal Berkshire FRS and Dorset & Wiltshire FRS were called shortly after 17:30.
Crews are working to stop the fire in the roof, which was well alight upon arrival, from spreading to neighbouring properties.
Specialist vehicles from Romsey and Fleet are also in attendance.
Fortunately, there have been no casualties reported as firefighters undertake a salvage operation and tackle the fire wearing breathing apparatus sets and using jets and hoses.