The McKinney Fire Department responded to a report of a structure fire at the 7300 block of Brayford Way on Sunday afternoon.
Fire investigators say the fire apparently started in the garage area and spread into the attic.
The house is severely damaged and unstable, making it dangerous for investigators working to determine the cause.
People inside the house were able to escape safely.
Two McKinney firefighters received non-life threatening injuries and were treated at the scene.