MFB firefighters took about 30 minutes to control a fire in a single storey brick veneer house earlier this morning.
It is believed the fire started in the rear of the premise at Grandchester Ave, Keilor East and quickly spread via the roof space into the rest of the building.
At the height of the blaze firefighters were unable to attack the fire internally as it was feared the roof would collapse.
The owner of the house was attending the gym when the fire was noticed by neighbours who were alerted by both working smoke alarms and a burglar alarm.
The damage bill has been estimated at $450,000 and the rest of the house will probably have to be demolished.
The cause is still being investigated and a watching duty will continue for some time.
Seven appliances and 22 firefighters attended the fire.
No information available to download