Weird Flue Build Up

[Jim Robinson]

The flue was covered with what looks like hard roofing tar. There were also little balls of it on the rain cap. Is this evidence of a chimney fire, or something else? It was a Lopi wood burning insert into a masonry fireplace and chimney.

[John Arnold]

I'm no chimney expert, but it looks like a nice build-up of creosote to me, and rather than evidence of a fire, is more likely going to lead to a chimney fire unless cleaned.

[Bob Harper]

Third degree glaze creosote. There may be some pyrolyzed creosote from a chimney fire down in there but I can't see it from here.

Should have been installed with a listed stainless steel insulated liner. You can try several methods to get some of this stuff out but they each have risks and are not 100%. Better to bust out these flue times and reline.

This is probably a "slammer" insert. If it has a direct connection to the first flue tile, it might have been acceptable prior to 2003 but now this flue would be oversized if the stove has a 6" collar.

Level II inspection and reline.