The Laval fire department said firefighters were on the scene within four minutes of the alarm sounding at the Villa Ste-Rose in Laval at 319 Marc-Aurèle-Fortin Boulevard.
By then, an evacuation was already underway.
"It was a scary experience. I was very shaken," said Jacqueline Massy, a resident of the Villa Ste-Rose.
Red Cross volunteers helped the home's staff assist evacuated residents, who found temporary shelter on a city bus.
The building was destroyed in the fire, but no one was harmed.
For those residents who are not able to stay with friends and family, Laval's Résidence La Luciole is offering 53 temporary beds. Former residents of the Villa Ste-Rose will be able to stay at La Luciole for the next few months until they can find a more permanent housing solution.
Firefighters have determined the cause of the fire was a short circuit in the building's attic.