Part of the reason why a chimney professional may not properly fix your chimney’s drafting problem with the first repair is because there are so many potential causes of poor chimney draft or chimney draft problems. I always recommend the least expensive repair first when it comes to diagnosing a chimney draft problem; avoid the chimney contractor who recommends a $3,000 dollar repair or chimney rebuild as the first option for correcting a chimney draft issue.
Air Tight Home
One of the most common issues that I have seen which results in a drafting issue is an air tight home. Whether you have a new home constructed with energy efficient doors and windows or an old home which has recently been made more air tight, a major cause of chimney draft problems (including smoking fireplaces) is that there is not enough fresh air being allowed to enter the home to provide sufficient supply for combustion. If there is not enough air in the home, the fire will draw air from down the chimney’s flue, causing smoke to flow into the room.
Burning unseasoned firewood can create excessive smoke which can create the illusion of a chimney draft issue and also cause creosote buildup. Make sure you are burning seasoned hardwood in your fireplace. Visit my articles on what wood to burn for information and specifications on what hard wood is.
Chimney is Too Short
If a chimney’s flue is too short, it may not be conducive to a strong, properly drafting chimney. The chimney must project at least 3′ above any point on the roof or building which it is within 10′ of. Chimneys may need to be taller to overcome a powerful downdraft or combat a particularly tall nearby building. There are flue extending chimney caps available and courses of brick can be added to the top of a chimney to make it taller as well.
Flue System is Too Small for the Firebox
Similarly, if the chimney flue’s diameter is not in proportion to the size of the firebox, there will be problems as well. Decreasing the size of the firebox by installing a SmokeGuard can help to solve this problem. A SmokeGuard is easily installed to the top of the front of the fireplace to decrease its overall dimensions. By decreasing the size of the firebox, smoke may more easily vent through the chimney, preventing poor draft from occurring.
Flue Too Cold
If the flue is very cold to start out with, the products of combustion may not be inclined to vent up, causing a smoking problem at the beginning of each fire. Lighting newspaper on fire and holding it up in the flue system for a few seconds warms up the flue and creates a strong draft from the very beginning. If you are experiencing a draft problem which involves smoke pouring into the living room you may want to consider warming the flue up first. If you have a buildup of creosote sticking the newspaper up into the flue to warm it could potentially cause a chimney fire.