A fire Tuesday evening caused heavy damage to a house under renovation on Valley View Lane in Clay Township, authorities said.

The owner was home but he was not injured. A damage estimate was not immediately available.

The state police fire marshal has been called to investigate, Dan Bunyan, chief of West Sunbury Volunteer Fire Department, said Wednesday, but the blaze about 6:20 p.m. was not considered suspicious.

The homeowner, whose name was not available, was out of the double-wide modular house working on his truck when he noticed the fire. He ran to a neighbor's house and called 911.

Unionville volunteer firefighters were first to get there.

“There was light smoke coming out from all of the overhangs,” said Nathan Wulff, an assistant chief with the Unionville VFD.

Officials believe the fire started in the back side of the house where there is a laundry room, bedrooms and a bathroom. Fire crews had to force open a door near the back porch to get inside.

Firefighters discovered it was an “oxygen-limited fire,” Wulff said.

“Basically, the house was all sealed up,” he said. “It was in mid-renovation and had new replacement windows that were installed properly. There were no air gaps so there was no ventilation in or out of the house.”

That, he noted, prevented the blaze from immediately taking off. Firefighters saw no flames when they first went in.

“The fire was sitting there, kind of in a stall,” Wulff said. “When the guys got in, they definitely noticed the high heat. It was very hot but there was not enough oxygen for combustion.

“The fire was burning very minimally, but as soon as we forced entry, we let a burst of fresh air in and then the fire started taking off.”

Firefighters found the fire in the hallway and laundry room, which is where officials suspect it started.

Using a mix of water and compressed air foam, the crew stopped the fire from spreading and had it contained in about 10 minutes.

Wulff said the incident should serve as a reminder to anyone who finds his or her home on fire: close all of the doors and windows before leaving,

“If that house hadn't been sealed up,” he said, “(the fire) probably would have been through the roof by the time we got there.”

The Prospect VFD assisted West Sunbury and Unionville firefighters.