Chimney specialist throws water on biomass bricks

FARMINGTON, N.H. - Folks using biomass bricks in their woodstove this heating season risk having any stove warranties voided, according to a chimney cleaning and flue repair specialist as well as warranty information provided by stove manufacturers.

Mark Jones of Chestnut Hill Chimney and Hearth said the biomass bricks, which are made of kiln-dried, super-condensed wood chips and sawdust, are portrayed as being good substitutes for cordwood, but really aren’t and can, in fact, damage your stove.

Jones said owners of new stoves who are considering using the biomass bricks should check with their stove’s manufacturer to see how their usage can affect any warranty.

Some manufacturers prohibit any noncordwood material, while other say one or two biomass bricks can be used and others will allow up to a third of a firebox.

But Jones, who is a NFI Master Hearth Professional, says buyer beware.

“Biomass bricks burn too hot, they can destroy stoves,” he said on Monday.

He said the people that make them haven’t done a lot of testing on them, and the stove companies haven’t done a lot of testing on them since they advise against their use.

He said he feels biomass bricks, which have been around about a decade, are OK to use sparingly if needed to help get green wood burning.

Jones said the long winter has proved very tough on seasoned wood supplies and woodstoves, too.

He said when most firewood dealers saw their seasoned wood supplies dwindle by February, people “were burning anything they could get their hands on.”

That meant a lot of green wood, a lot of creosote and probably 50 percent more plugged flues than a normal winter, he said.

Besides the green wood, biomass bricks also became popular.

With a couple month of heating season still ahead of us and after stoves were worked unusually hard since December, he advised woodstove users to check their chimney and their stovepipes to make sure they’re safe. He said to check your chimney, just find the chimney door in the cellar or outside, grab a mirror and a flashlight and check for creosote. He said if you can pry more than a third of an inch off the side of your flue, you need another cleaning.

If the creosote is glazed you risk a chimney fire and need a cleaning now.

To check the stovepipe just tap it a couple of times. If you hear a little creosote falling, you’re OK. If you hear a lot falling, that’s not good. And if you hear a solid thud, with nothing falling, you need a cleaning now.

Jones said folks should consider having their chimneys and stovepipes cleaned in the spring or summer when the rates are generally lower.

For more info go to http://chestnuthillchimney.com.