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Dirty chimney presents a fire hazard
Oct 01, 2004

Well, fall is upon us and now is the time we should start preparing for winter. 

While some can get away from it all and bask on a sunny beach, most of us have to stay at home and suffer through another cold winter. 

To soothe the suffering, there is nothing better than to sit in front of a flickering fireplace, all nice and cozy while sipping on your favourite beverage. 

Flickering flames have a calming effect and give rise to thoughtful memories such as when was the last time you had your fireplace chimney inspected or cleaned. There are not many things scarier than a chimney fire in the middle of the night. 

I talked to a master chimney sweep who said that a chimney that hasn’t been swept for a couple of years or more should be cleaned immediately. Dirty chimneys are a hazard waiting to happen. 

He pointed out that most chimney flares are a result of creosote buildup. Creosote is a colourless, oily fluid produced by slow-burning fires in airtight stoves or fireplaces. It is a product of incomplete combustion of the gasses from wood that condense inside the chimney. Once there is a sufficient buildup of creosote, it doesn’t take much to ignite it. 

Temperatures produced by a chimney fire can reach up to 2,000°F without difficulty. Such high temperatures damage the inside of the chimney and may cause the mortar between the bricks or chimney flue sections to melt. 

The damage can be significant and the chimney may have to be rebuilt at considerable expense. Replacement may entail removing walls, cutting holes in the ceiling and roof, as well as installing a concrete base strong enough to support the weight of the chimney. 

The basic chimney structure may be sound after such a fire, but the liner may have to be replaced. The cost of this, depending upon the height of the home, can run into several thousand dollars. 

Homes built years ago may be more susceptible to damage than newer homes since building codes were not as demanding at the time these homes were built than the codes are today. In older homes, the wood used in the construction process could be close to the chimney. Added to this, the wood used in the home construction is probably bone dry now and the fire flash point could have been significantly lowered. 

For your protection: 

• Use only seasoned wood. 

• Build smaller, hotter fires that burn more completely and produce less smoke. 

• Never burn cardboard boxes, wrapping paper, trash, plastic or pine trees  — they can spark a chimney fire. 

• Avoid smoldering, overnight burns. 

• Ensure a good draft and a proper chimney size. 

• Never burn painted wood, driftwood, particleboard or plywood. 

• Refuel more often with smaller loads. 

• Artificial logs are not recommended.