22 Firefighters attended fire on Lapwing Close in Williams Landing last night at approximately 11.30 pm
Arriving within six minutes, firefighters wearing breathing apparatus found flames coming from the back of the single-storey brick house spreading rapidly.
Five Pumpers, a Rescue, Ladder Platform and three support and specialist vehicles were assisted by Ambulance Victoria paramedics and Victoria Police.
The scene was brought under control 30 minutes later with no reported injuries. Some minor damage was sustained to a neighbouring fence and garage.
The structure functioned as a childcare centre and residential house.
Crews remained on scene overnight with specialist fire investigators determining cause.