A car was targeted by arsonists in Springbourne, Bournemouth, overnight.
Flames spread to a shed and fence at the property in Richmond Park Road at 3.05am.
Firefighters from Christchurch wearing breathing sets extinguished the blaze.
The fence panel and part of the shed were destroyed and a nearby car suffered minor heat damage.
A Dorset Fire and Rescue Service spokeswoman said the cause was "doubtful".