WAUSAU, Wis (WSAU) A house fire on the 300 block of Flemming Street in Wausau is under investigation.

It happened on the second floor around 630 yesterday. When firefighters arrive, the flames had spread to the walls and roof. A part of the roof had to be opened to vent the fire and to allow firefighters access.

The cause of the fire is unknown. The home was vacant. It had recently been sold and was being renovated by the buyer.