Ottawa police and firefighters continue to investigate an overnight fire at an Ottawa office building.

Firefighters were called to the two-storey building at 1755 Woodward Drive, near Maitland Avenue and Highway 417, around midnight.

The first crews quickly sought help as the fire escalated to a third alarm. But with the added crews, the blaze was extinguished within the hour.

The fire started in an office at the front of the building, which belonged to Tega Homes, and was contained there. Some of the other businesses in the building did have some smoke and water damage, though.

One officer remained at the scene Tuesday morning to guard the property as the building, which is believed to have included at least six businesses, remains closed.

There was nobody inside the building at the time of the fire and there is no indication if the fire has been deemed suspicious. Damage is estimated at $300,000.

The building has been home to numerous businesses including the Canadian Council for Family Safety and various contractors.