Approx fifty firefighters and officers have been scrambled to the incident on St James Road in Southampton after the blaze ripped through a property that is understood to be the old coach house at around 11.30pm on Sunday evening.
St James Road and part of Bellemoor Road has been closed and drivers are being asked to avoid the area.
Locals residents on St James Road are being advised to keep all windows and doors closed due to a large amount of smoke issuing from the building.
The cause of the blaze is not currently known.
Firefighters are expected to remain until the earlier hours.
South Central Ambulance have also sent a HART team to the incident.