A fire Monday afternoon destroyed a house under construction in rural Thunder Bay.

The fire broke out at a building site on Mountain Road.

The Thunder Bay fire service says a contractor had been working on the two-storey house, and called in the alarm.

Platoon Chief Dave Long said the fire was well underway by the time crews got to the scene. "We arrived and the house was fully involved...the fire spread quickly throughout the building," he said.

Long said the damage was "pretty bad", especially on the second floor but also on the main floor. 

He said a pumper truck broke down on the way to the fire so a substitute vehicle was sent, but the firefighting effort was not affected.

A nearby resident said the owner of the house is currently out of town.