Ann Hayward said the community had rallied around the family after it was discovered their insurance did not cover the 5m-wide hedge that ran along one side of their property.
The fire was thought to have been started by hot ashes on a neighbouring property.
Bunnings Warehouse had "generously" built the new fence and the tree house after a community working bee had taken out the burnt hedge, she said.
Her children were now able to play in the garden safely and she thanked everyone who had helped make that possible.
"It's made such a difference. People have been really supportive."