A house in the Goulds neighbourhood of St. John's was extensively damaged on Thursday night.
The fire on Gary Drive was reported around 7:30 p.m.
Firefighters from three stations responded.
The Royal Newfoundland Constabulary said the site was too hot for investigators to go inside on Thursday night. They were expected to return to the scene Friday.
No one was injured during the fire, although police described the damage as extensive.