Shortly after 6 p.m. on Saturday, firefighters were called to the Hampton Village neighbourhood, in the northwest of the city.
A single house with a basement apartment and a duplex was engulfed in flames, with the roof of the first building already destroyed by the time firefighters arrived.
In a statement, the fire department said the blaze was caused by the “improper disposal of smoking materials.”
The statement also said the fire was accidental and that it began between the two structures and quickly spread.
The cost of the damages has been revised to more than $1.3 million.
The statement concluded with the fire department advising Saskatoon residents to properly dispose of smoking materials in metal, ceramic or glass containers with sand or water at the bottom and tight-fitting lids.