Fireplace Is Not Drawing Correctly

Chimney Height

• A low chimney can prevent a fireplace from drawing properly. According to The Chimney Sweep, a masonry chimney must extend 2 feet higher than any structure within 10 feet. If surrounding structures are taller than the chimney, downward wind pressure may direct air down into the fireplace, where the pressure is lower. Although hot air rises, pressure from the cold downward draft will seek to equalize the air pressure by pouring cold air into the room. A professional chimney repair service can add an extension to increase the chimney’s height.

Firebox Size

• The firebox, which is the area of the fireplace in which the fuel burns, must have the correct proportions and shape to draw the smoke up the chimney. The firebox opening should be wider than the back, and the rear wall should lean toward the opening. The building code in your area will require specific firebox size and proportions. According to Ask the Builder, an improperly proportioned firebox may require professional reconstruction.

Blocked Flue

• A professional chimney sweep can inspect your chimney each year for blockages, which can prevent adequate drawing and increase the risk of chimney fires. The chimney sweep can remove soot, creosote buildup, leaves or other flue blockages that may interfere with drawing. If you can climb onto the roof, you can use a chimney brush to clean the chimney each month that it is in use. A flue that is less than or greater than one-tenth the width of the firebox opening can prevent hot air from rising past the heavier cold air. A fireplace or chimney repair service can install a new flue liner, or add masonry to create a narrower fireplace opening.

Cold Flue

• If your fireplace does not draw properly when the weather first turns cold, a cold chimney flue may be the cause. When the flue is cold, the heavier cold air rushes from outside into the warm fireplace. An open window in the same room as the lit fireplace will equalize the pressure and draw hot air and smoke from the fireplace toward the chimney. The Michigan State University Extension states that you can prevent this problem by preheating the flue. Place rolled newspaper in the fireplace, light the newspaper and let it burn for five minutes or until the smoke rises toward the chimney.