A shed fire spread to a house in Waddon last night after a small gas cannister exploded.
Firefighters from Croydon fire station were called to Violet Gardens at 11.44pm to reports of a shed alight.
When crews arrived, a small gas cannister inside the shed had blown up, causing the fire to spread to the house.
An adult, teenager and child inside the property were woken by the explosion, which broke an upstairs window.
The group escaped uninjured and the fire had just started spreading to the roof as firefighters arrived.
Red Watch manager Harvey Payne said: "The crew got straight up into the roof and stopped it spreading in the roof and on the first floor.
"They did very well and limited the damage in the house to five percent of the roof and five percent of the first floor.
"We had it all under control within about 20 minutes, but remained at the scene damping down for a couple of hours.
"The heat melted some of the guttering from the corner of the house next door, so we checked that out too."
The cause of the fire is under investigation.