Four families have been left homeless after a fire ripped through a multi-unit house overnight in Barrie.

Barrie fire tells CTV News the families were inside four units in the building on Parkside Drive. Flames could be seen shooting through the roof of the home, but firefighters were eventually able to get the blaze under control.

Investigators say the roof collapsed as a result of the fire, but fortunately no one was injured.

“I smelled smoke in the air and thought someone was having a campfire and then I heard some weird sounds,” says area resident Chris Simis. “I went out and saw the house was on fire. I ran outside, opened the door and it was just clouds, clouds of smoke.”

It was Simis banging on Iris Wingate’s door that warned her to leave her basement apartment. “I heard a lot of banging and they said our house was on fire,” says Wingate.

One bystander says, “if it wasn’t for the young guys there that woke them up there might have been causalities there, you don’t know.”

Damage is estimated at $500,000 and the cause has not yet been determined.

Barrie police have arranged shelter for the families.

The Ontario Fire Marshal’s Officer was on scene Saturday investigating.