Maintain a clean fireplace for winter safety

Professional inspections and regular maintenance can prevent chimney fires — and save lives.
By James Dulley
Maintain a clean fireplace for winter safety

This patch system repairs and seals the flashing around the base of the chimney. A piece of mesh is covered with a tough polymer material that adheres well.

Tens of thousands of chimney fires occur every year due to creosote buildup and other chimney problems. In many cases, the entire house ends up burning down and lives are lost. These chimney fires result in as much as $200 million in property losses each year.

If you notice reduced draft up the chimney, schedule an appointment with a professional chimney cleaner. It may turn out that the screening in the chimney cap was just clogged with soot and blocked the air flow up the chimney. Tapping the screening with a rubber mallet may be enough to knock the soot loose. Later you can replace the chimney cap with one with a more open mesh.

If a creosote fire occurs inside your chimney, the fire's heat can cause the tile liner to crack and fall from the masonry wall. When this happens, the broken tile may restrict the air flow up the chimney reducing the draft. You should able to see a broken loose tile when looking down the chimney with a bright light.

A chimney fire can also cause the creosote to puff up. It expands and feels somewhat like plastic cooler foam. If you can run a brush down the chimney, some of this puffed creosote may fall down into the firebox. If you find either a broken tile or puffed creosote, your chimney will definitely need a professional cleaning and inspection with a camera.

If repairs are needed, get estimates from several chimney maintenance companies. In my own case, one chimney company found puffed creosote and claimed the tiles were also loose. They gave me a quote of $7,000 to repair my chimney. Another company cleaned the chimney, then inspected it with a camera, but found no broken tiles. For $200 total, they also sealed the chimney crown, and my fireplace has worked fine for years now.

There are some things you can do to reduce creosote buildup. First, use well-seasoned wood and do not try to choke off the combustion air too much to extend the burn time.

Special fireplace logs are available which contain chemicals to reduce creosote formation in the chimney. Using these periodically can help keep the chimney clean. SaverSystems (800-860-6327, www.saversystems.com) offers a spray to use on regular wood logs and other cleaners to minimize creosote.

Much of the hazardous damage to chimneys is caused by moisture entering from outside. This moisture can migrate through the brick and the mortar joints into the chimney. This is bad everywhere, but particularly so in cold climates with a repeated freeze/thaw cycles during winter. Use a water- or solvent-based sealer on the chimney bricks and mortar.

The crown of the chimney is another location for moisture to enter. Tap on it lightly with a hammer to locate any loose areas and brush them away. If the crown is still in good condition, coat it with a special elastomer crown repair compound. If you have a problem during winter, SaverSystems offers a special crown sealer that cures in below freezing temperatures.

Check the condition of the mortar joints. Where you find loose mortar, fill in the gaps with a elastomer concrete-colored sealer. Also, inspect the flashing where the chimney meets the roof. Deteriorated areas can be sealed with a flexible flashing repair compound.

About the Author

James Dulley is an engineer and syndicated columnist for the National Rural Electric Cooperative Association. www.dulley.com

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