Chimney Drafting Problems - Smoky Fireplace & Chimney Obstructions

Smoky Fireplaces

Residents from Milwaukee, Menomonee Falls WI, Elkhorn WI, Beloit WI, Muskego WI, Brookfield WI, Mequon WI, Delavan WI, and the surrounding towns trust us to service & repair the chimney and fireplace systems.

fireplace smoking in Burlington WIIf you have a smoky fireplace, there is a drafting malfunction in your chimney.  Drafting is the process in which combustion products from a fire draw up and out of your chimney into the outdoor atmosphere.  It can be dangerous for combustion gases to enter your home; for example, there is the possibility of exposure to deadly carbon monoxide. There are numerous reasons why a fireplace is smoky, and if often requires the help of a chimney professional to pinpoint the problem.  The following are some of the common causes of a smoky fireplace:

Negative Air Pressure

Based on the fact that heat rises, a chimney is designed to dispel smoke and gases from a fire.  Heat rising is also called the “stack effect.”  As hot air is exiting through a chimney, cooler air should replace it; if it doesn’t, the hot air will backdraft and flow into the house instead of up the chimney.  One reason cool air doesn’t replace rising hot air is because a home is sealed very tightly, which stifles the drafting process.  An appliance such as a clothes dryer pulling air from the room into a vent is another cause of negative air pressure.

Faulty Structural Design

The fireplace and chimney together have numerous components.  Sometimes the heating system is improperly designed, and the result can be a smoky fireplace.  An example is that a firebox can be the incorrect size for the flue, but there are actually many different components which could end up being the culprit when a chimney doesn’t work as it should.  Our chimney professionals understand all the ins and outs of chimney anatomy and can determine whether there are structural problems causing the fireplace to smoke.

Clogged Chimney Cap Mesh

Chimney caps with mesh or metal screens are important accessories installed at the top of the flue.  The toppers prevent rain from falling into the chimney flue, they prevent animals from getting into your chimney, and they have spark guards which can prevent the roof and nearby combustible products from catching fire.  There are times, however, when the screen on the chimney cap becomes clogged, which can result in a smoky fireplace.  Chimney caps can be jammed by creosote deposits, leaves, insect or animal nests, and other debris.

Improper Use

For proper drafting, a fire should be made in a grate so that the fire gets needed oxygen.  Also, without a fire grate, there will be so much smoke that the fire won’t get hot enough to ventilate properly.  The fire should be built toward the back of the firebox, no more than an inch away from the back wall.


Chimney Obstruction

When a chimney gets clogged, the flue can become so narrow that combustion products can’t properly exit the chimney, resulting in a backdraft.  There are many different types of chimney obstruction, and a few examples are:  an animal builds a nest in your chimney, there is an excessive accumulation of creosote, masonry is deteriorating and falling into the flue, and leaves or other types of debris have collected in the flue. Clearing the blockage can help combustibles escape properly and solve smoky fireplace problems.

burning the wrong kind of firewoodWet or Green Firewood

Nice, clean fires are the result of using seasoned wood.  If you burn wet or green wood, on the other hand, the fire may not burn hot enough for the hot air to rise, which causes the combustion gases to exit into the room instead of up the chimney.

Chimney Height

If a chimney isn’t built high enough, particularly in consideration of the height and slant of the roof, there may be problems with drafting.  It’s sometimes necessary to add more height to a chimney, to fix the problem of a smoky fireplace.  This is a technical issue that requires the knowledge of a professional since a chimney that’s too tall can also cause a drafting problem.

Our chimney sweep professionals have the expertise to identify the cause of a smoky fireplace, even with all of the many possibilities.

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