Four fire engines attended the incident, which caused severe damage to the roof of the building.
Cleveland Fire Brigade said an investigation is underway.
It took four hours to contain the flames and crews left the scene at around 10.20pm.
Cleveland Fire Brigade said: “We were called to a fire on 30.06.2022 at 18.17 in Owton Manor Lane, Hartlepool.
"Four fire engines attended from Hartlepool, Billingham and Saltburn. Fire was in a disused ex farm building. Severe damage to roof of building. Carp used, 3 jets and ground monitor.
"Fire investigation is underway as per our usual procedures. We left the scene at 22.19.”
Crews were also called to the farmhouse at the start of June when two jets and a water cannon were used.