The fire broke out around 10:30am on Milby at Ball, just east of downtown Houston.
Firefighters said the homeowner left used charcoal in a plastic container next to the house. It reignited, sparking a fire that spread to the house.
All residents made it out safely and no one was hurt, officials said, but the fire destroyed the attic and did significant damage to the rest of the house.
According to firefighters, charcoal can stay hot for 48 hours. They recommend keeping it in a metal container until it's completely cold and dousing it with water before throwing it away.