A blaze that started behind a fireplace heavily damaged the second floor of a vacant Palmerton home late Saturday night.

Crews were called by a neighbor to a residence in the 200 block of Lafayette Avenue just before 10 p.m.

“The investigator found that the firebox at the fireplace had some failure points and wasn’t quite sealed up properly,” Palmerton Fire Chief Jason Behler said Sunday.

The home was vacant but the owners, who had been doing renovations, were there earlier in the evening and put out a smaller fire in the fireplace.

While it appeared all was well, the fire was burning behind the fireplace and took off through the fire stop, up the wall to the second floor and into the attic.

“With some of the older construction, it really balloons and there isn’t much you can do to stop it,” Behler said. “Our guys did get a pretty quick knock down though. When it burned through the roof, that is when we get in there to really stop it.”

No firefighters were injured, but a massive amount of smoke did make vision inside the home difficult.

“I think one of the most challenging things was the fire really didn’t show itself because it was behind a wall,” Behler said. “But the smoke was banked down on the first floor and it was difficult for guys to see to get up to the second floor, where most of the fire was.”

Crews were on scene until around shortly after 2 a.m.