The Roanoke County fire marshal's office is investigating the cause of a house fire Wednesday that took crews more than an hour to get under control.

Firefighters from the county and Salem were called to the wood A-frame house in the 1300 block of Skyview Road about 3 p.m., Roanoke County Fire and Rescue spokeswoman Jennifer Conley Sexton said.

When they arrived, crews saw flames coming from the roof and windows on three sides of the house, battalion Chief Rodney Ferguson said. The roof had partly collapsed by the time firefighters put out the blaze.

There are fire hydrants along Skyview Road in West Roanoke County, but crews had a difficult time getting a water supply to the house because it sits at the end of a long driveway up Little Brushy Mountain, Ferguson said.

He did not know where the fire started, or whether anyone was home. There were no reports of injuries.

A damage estimate was not available Wednesday.