Unsafe Drafting: What Chimney Pros Want You to Know

When your chimney operates properly, a draft is created that supports proper combustion and draws hot exhaust gases up, expelling them safely from your home. Hot air rises because it has less density than cold air. Oftentimes, chimneys do not draft properly, resulting in a smoky fireplace. Combustion gases are toxic and can cause respiratory problems. They also contain deadly carbon monoxide, and it’s important to have the problem repaired. More information about unsafe drafting follows.

Causes of Improper Chimney Drafting

Poor Chimney Construction

The dynamics of chimney operation practically demand proper construction. If a chimney, for instance, has dimensions that are improper for the fireplace or heating appliance it is attached to, drafting issues will likely occur.

Draft can also be negatively affected if the flue is subject to filling with cold air. Although heat rises, it can’t always escape upward through a thick column of cold air. This problem is also more prone to occur if the chimney is too short to create a proper draft.

The Stack Effect

In multi-story homes, the “stack effect” can occur. This problem is caused as a result of heated air rising to upper stories and leaking large quantities of air. This can create negative air pressure stronger than the chimney draft. A temporary solution for the stack effect is to open a window or door near the heating appliance. A long-term solution would be for a supply of cold air from outside to be directed into the firebox, though this may not be possible based on the location or style of the fireplace or stove.

Another potential solution for the stack effect is to have a flue extender installed. Hot air seeks to go to the highest point in a building envelope. If your chimney isn’t the highest point, combustion gases will be drawn back into your house in the effort to reach the highest point.

Obstructions

A common issue chimney sweeps see is that a chimney hasn’t been cleaned routinely and a buildup of creosote deposits obstructs the flue lining. Sometimes the mesh on a chimney cap is where an obstruction occurs. If the mesh is too fine and fires don’t burn hot enough, the combustion byproducts have enough particulate matter to clog the chimney cap. Chimney cleaning and/or chimney cap cleaning is needed to resolve the problem.

Signs of Improper Drafting

It makes sense if you have difficulty starting a fire on a warm day because the temperature differential between the outside air and your heating appliance may be too similar. If it’s a cold day and the fire won’t start, you may need to prime the flue. This is typically accomplished by creating a newspaper torch and holding it up toward the open damper. It can take a couple of tries to dispel the cold air filling the flue enough that the chimney draft operates properly.

Contact the Chimney Specialists Inc.

In the tri-state area, the top fireplace and stove store that offers chimney repairs, chimney services, and full-service installations is Chimney Specialists Inc., which is located in Highland WI. The certified chimney sweeps at Chimney Specialists can pinpoint the cause of your drafty fireplace and find the best way to restore a proper draft. If your chimney has an unsafe draft, contact us without delay. Contact details follow.

Chimney Specialists Inc.

869 Main Street, Highland, WI

Phone – (608) 929-4887 / Toll Free (800) 395-6660

Dubuque Fireplace & Patio

925 Century Drive, Dubuque, Iowa

Phone – (563) 582-5156