A house fire in southwest Guelph caused significant damage Wednesday night.

Firefighters were called to a home on Picadilly Place around 10:15 p.m. when a neighbour noticed the fire.

Upon arrival, they found flames shooting out of a bay window at the front of the house, as well as a basement window.

“It was confirmed that we had a working house fire,” Guelph Fire Department fire prevention officer Craig Bottomley told CTV News.

The family of two who live in the building weren’t home at the time of their fire.

After arriving, firefighters attacked the fire aggressively, quickly bringing it under control – but by that point, it had already done significant damage to the house.

Smoke and heat damage also permeated throughout the residence, and fire officials say the home is no longer inhabitable.

“Part of the (main) floor did collapse into the basement,” Bottomley said.

“The family will not be able to move back in. It’s totally unlivable.”

Firefighters found three of the family’s seven cats dead, while the other four remained unaccounted for as of Thursday afternoon.

The cause of the fire was not immediately clear.