A fire that spread quickly through a north Cambridge home has left a couple homeless.

The fire broke out in the carport of a Thorman Drive residence, near Speedsville Road and Eagle Street, Monday evening.

Next-door neighbour Dave Marion was outside barbecuing at the time.

“I noticed the smoke from my barbecue going between the houses,” he told CTV.

“It seemed like too much smoke so I went to take a look, and that’s when I noticed the smoke coming out of their eavestrough and knew that it was a fire.”

Marion started pounding on his neighbours’ door, alerting them to the fire they had not noticed.

Neighbour Heather Nicholls was across the street when she noticed the flames.

“I ran out real quick and I noticed that the left side of their garage was totally full of flames,” she said.

Nicholls went back inside to tell her kids about the fire. Looking across the street again three minutes later, she saw that the flames had spread and engulfed the entire roof.

Fire officials say the building’s occupants, a husband and wife in their 60s, were home at the time and being visited by other family members.

All were able to escape the building, as was the family dog.

Firefighters from four stations were called to Thorman, and smoke could be seen from the fire station at Bishop Street and Franklin Boulevard.

Much of the house’s structure remained intact following the fire, but the home’s carport was destroyed.

“We do have significant smoke and water damage to the interior of the home,” said Cambridge Fire captain Mark Yantha.

Electrical causes have been ruled out, but Yantha says the fire may have started when some garbage in the carport caught fire.

Damage is estimated at $175,000 and the cause of the fire remains under investigation.