A house under renovation on Lennon Lane suffered extensive due to a fire on July 3.

Firefighters responded just after 2 p.m. to the house after a neighbor called in a report of heavy smoke coming from the chimney area. Wilton Fire Capt. Kevin Czarnecki said when firefighters arrived, they also saw smoke coming from the roof line.

No one was at home and there were no pets inside. “We got to the front door and had to force it open and we were met by heavy smoke and heat,” Czarnecki said.

The fire was contained to the main floor of the one-story home that has a basement and attic. It appears to have started against one of the walls in the family/living room area, Czarnecki said. Fire Marshal Rocco Grosso and Assistant Fire Marshal Kevin Plank were on scene and their investigation is continuing.

The house sustained extensive smoke damage and a large amount of heat damage, which Czarnecki described as things like blackening and peeling paint, but not structural damage. The fire did not get into the attic, he said.

Czarnecki said he did not know how long the fire had been going, “but it must have been going a little while. I’m guessing there might have been a window open to help draw the fire to other parts of the house.”

About 20 firefighters battled the blaze, which they had under control in half an hour, but they remained at the scene until after 4 p.m. A crew from Eversource came to turn off power to the house.

Among the firefighters were crews from Westport, Weston and New Canaan. Ridgefield responded to cover the firehouse in Wilton Center. Wilton responded with Engine 1 and Truck 5 from headquarters and Engine 2 from Station 2 on Ridgefield Road.