Ottawa firefighters were called to 6203 Elkwood Dr just before midnight Tuesday as flames were reported coming from the roof of a 2-storey, 3000 square foot home.

Initially, firefighters took up a defensive position outside the home. Crews were able to bring the blaze under control in about 90 minutes.

The owner wasn't home at the time of the fire.

The damage to the home is estimated at $500,000.

The cause of the fire is not yet known.

The Ottawa Police Arson Unit is investigating.