About 20 firefighters were called to the scene and spent hours trying to put out the flames.
Fire officials said the fire broke out at around 1:30 p.m.
No one was injured.
The building housed a family of five, as well as a retail business that was closed at the time.
Mark Bonspille, who owns the property, told CBC News that he was out on a lunch break and returned home to see his house and shop in flames.
"Everything — my business, my home — it's all, all gone. It's maddening, in a sense. All the stuff I worked for, for years," Bonspille said, adding that his home and business insurance had expired.
"But you know, I have my kids, that's the main thing. My kids are safe, and I'm safe. That's all that matters to me."
Bonspille said he and his family will likely stay with relatives for now.
Investigators are looking into the cause of the fire.