Crews rushed to the house on Villa and Belleview just before 3 p.m. Sunday. They saw heavy flames and smoke coming from the garage area.
A captain at the scene says the residents evacuated themselves and no one was injured, but crews faced a challenge in fully containing the fire.
"Multiple roof layers made it difficult to find all the hidden parts of the fire, so we were probably involved in fire attack for approximately one hour before we called it contained," said Glen Hall, Porterville Fire Department.
Hall said about half the home was damaged. The cause is still under investigation.