Why Does My Chimney Keep Getting Clogged Up?

Mesh

• Too small of a wire-mesh screen on the chimney cap can contribute to chimney clogging, especially when the weather is cold or when burning conditions are not strong. The mesh opening should be about 1/2 to 1 inch across, as a mesh with a opening less than 1/2 inch likely becomes clogged in any situation. The right-size meshing keeps critters out of the chimney while not allowing outside debris in.

Outside Obstructions

• Debris such as leaves and snow quickly clog a chimney cap’s mesh screen, so check this area and clean it once a year. Use a wire brush to remove any debris present in the screen. Bird nests also can be lodged in a chimney cap or inside the chimney and collect more leaves and other clog-causing debris, so check for the presence of animal nests prior to using your chimney each year; do this by shining a flashlight down the chimney.

Flue

• A buildup of soot at the base of the chimney flue often causes a clogged chimney. A buildup of creosote -- a gummy, flammable substance that is the result of burning wood -- inside the flue indicates a problem that a professional chimney cleaning company should address. When 1/8 inch of sooty buildup is present in open masonry fireplaces, the chimney needs to be cleaned, according to the Chimney Safety Institute of America. An acid or chemical treatment likely is the only way to get rid of this sticky creosote substance.

Wood Selection

• Your chimney becomes clogged more quickly if you use wood that has a high amount of moisture in it. Also, producing a fire that lacks an adequate amount of air can cause clogging because more creosote forms in the chimney and chimney cap when less-complete combustion occurs. Avoid burning papers in your fireplace, which generates tiny pieces of ash that get caught in the chimney cap mesh screen.