The Houston Fire Department said firefighters responded to the Rug Mart right around midnight in the 5900 block near Fountain View.
The Houston TranStar cameras showed heavy smoke lingering from the building and over onto lanes of traffic.
Initial information said the fire may have begun at a tire shop behind the store, before it eventually grew, HFD said.
HFD said firefighters called in extra help to battle the fire. About five hours later, the fire was put out.
HFD later said in an update that they will remain in the area all day to monitor hotspots as arson investigators look at the potential cause.
Officials with hazmat will look at the air quality throughout the day.