The blaze broke out at a home in Springhill Crescent, Madeley, at about 12.30am on Monday.
Three fire crews from Telford Central and Tweedale went to the scene and four firefighters went into the house wearing breathing apparatus to tackle the blaze protected by a covering jet.
It took an hour and a half to bring the ground-floor fire under control.
Fire Investigations Officers were at the scene along with police officers
Shropshire Fire and Rescue Service returned to the scene this morning and confirmed the fire was started deliberately.
It comes five days after five cars were destroyed by arsonists in one night in nearby Brookside.