A poorly constructed chimney sparked a fire at an Atascadero home undergoing a remodeling Wednesday evening.

Shortly after 5 p.m., a fire was reported at a vacant house under construction at 7850 Curbaril Avenue. Firefighters arrived and found smoke coming from attic vents.

Responders then used thermal imaging cameras to locate the fire inside the first and second floor walls. Firefighters contained the blaze within 30 minutes, limiting the damage to the walls, flooring and attic.

Atascadero fire officials say construction workers had been burning wood in the fireplace at the house, and the fire spread into a wall because of a design flaw in the chimney. No one suffered injuries as a result of the blaze.