Police are investigating a fire last month at a derelict Grade Two listed farmhouse near Exeter, after confirmation that it was started deliberately.
East Devon council was due to start work shoring up Tillhouse Farm in Cranbrook - but the building has now been severely damaged by the fire, including the loss of its whole roof structure.
However the council will try to preserve what it can of the 15th century building.
The fire was started in the early hours of December 15th - police are appealing for witnesses.