FIrewood
Wood for use in home fires should be cut, split and stacked for drying at least 4 to 6 months before burning. Burning wet wood promotes creosote deposits.


No doubt. January was cold, and the rest of the winter promises more chilly weather.

University of Tennessee Extension forestry specialist Wayne Clatterbuck recommends that those who have been keeping the chill at bay with fires in their fireplaces or with wood-based heating systems be sure that their chimneys are creosote free. “If you didn’t have your chimney checked for creosote before winter, take advantage of some temperate weather and get it checked,” he said.

A creosote layer of one-quarter of an inch or more should be removed by wire brushing to prevent a chimney fire.

Creosote is a highly flammable fuel that is carried in the smoke of a wood fire. It condenses and is deposited on walls of a cool chimney or on the stovepipe walls that connects the heater to the chimney. Creosote also forms inside the fireplace and the wood heater.

Clatterbuck says creosote has several forms. “It may be lightweight, fluffy and ash-like in appearance. This type is easily removed by wire brushing. A second form is a black, hard, crusty buildup that forms on the flue and stovepipe walls. This buildup is more difficult to remove,” he said.  “The most difficult form of creosote to remove is the glazed or enamel-like coating on walls of a wood heating system. This form is called third degree creosote. It cannot be easily be removed by wire brushing and should be removed by professional chimney sweeps.”

To reduce the amount of creosote deposited by burning wood, Clatterbuck recommends that only dry wood be burned. “The wood should be cut, split and stacked for drying at least 4 to 6 months before burning,” he said. Why?  Clatterbuck explains, “About half the weight of fresh cut or green wood is water. The water is evaporated from the wood as steam when the wood begins burning. This reduces heat from the fire and living area and causes the cooler smoke to condense on the flue as creosote.”

Other ways to reduce creosote buildup is to build the fire so that it starts burning as soon as it is lit. This may sound simple, but Clatterbuck says people make fire-building mistakes routinely. “One way to build a fire is to lay crumpled newspapers on the bottom, add some small kindling and then put on several small pieces of firewood until the fire is burning well. Light a crumpled newspaper and put it on top of the wood before lighting the fire. The heat from the burning paper will help the chimney draw the smoke up faster,” he said.

Home wood burners who want to maintain a fire in their woodstoves over a long period usually fully load their stove and almost completely close off the air supply. This practice maintains a slow burning, smoldering fire that causes creosote deposits. Clatterbuck recommends burning a smaller amount of wood and keeping the wood heater drafts open more in order to produce a hotter fire. If this is not possible, the stove drafts and damper should be kept wide open for about 30 minutes a day so that the fire burns hot to reduce creosote deposits.

UT Extension provides a gateway to the University of Tennessee as the outreach unit of the Institute of Agriculture. With an office in every Tennessee county, UT Extension delivers educational programs and research-based information to citizens throughout the state. In cooperation with Tennessee State University, UT Extension works with farmers, families, youth and communities to improve lives by addressing problems and issues at the local, state and national levels.

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Contact:

Wayne K. Clatterbuck, UT Department of Forestry, Wildlife and Fisheries, 865-974-7346, wclatter@utk.edu

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