U.S. Inspect Home Inspection:

Advisory Report

October, 2003

Chimney Maintenance

October is the season for leaves to change color, ghosts and goblins to come door-to-door asking for candy, and … for your fireplace and chimney to be cleaned. Just as you should have your air conditioning unit serviced and cleaned in the Spring, it is recommended that you do the same for your chimney prior to use in the Fall. Regular cleaning and inspection of your chimney will help to insure safety and efficiency when using your fireplace.

Wood burning fireplace chimneys should be inspected and cleaned every year or after burning about three to four cords of firewood. If a chimney is used regularly, it must be cleaned before it can be inspected. Having your chimney inspected when it is swept is always a good idea as the additional cost is minimal and the benefits can be substantial. The most important reasons for cleaning and inspecting your chimney are safety and efficiency.

When firewood is burned, it produces a byproduct called creosote, which builds-up on the inside of the flue. Creosote is flammable and can cause chimney fires, which is one main reason why the excessive build up of creosote is so important to prevent. Another important chimney safety issue is inadequate venting. If the flue is not properly sized for the fireplace, blocked, dirty (has excessive creosote build up), cracked or has holes in the flue, the flue may not vent the exhaust gasses properly. This can allow carbon monoxide to enter the living area.

A cleaner flue will allow the fire to burn more efficiently and emit more heat. A dirty chimney will cause the fire to burn slower. Below, we put together a quick checklist of what to have inspected when your local chimney professional comes out to clean your chimney.

Exterior Inspection

Check for deteriorated, cracked or spalling brick at the chimney exterior.
Check for deteriorated, cracked or missing mortar.
Check for exterior staining that is indicative of flue gasses seeping through the chimney structure.
Check the chimney cap to insure it is secure and not damaged or deteriorated.

Interior Inspection

Check the flue for cracks in the chimney liner.
Check the flue for creosote build-up.
Check the flue for blockage due to debris or animal nests.
Check the firebox for cracks and deteriorated mortar.

There are several steps that you can take while your fireplace is in use to keep your chimney operating safely and efficiently.

Choose your wood wisely. Seasoned hardwood will produce less creosote than other types of wood. Burning green or unseasoned wood will cause more smoke and contribute to a greater accumulation of creosote in the flue.
Keep the damper open when using the fireplace to allow better draw of the exhaust gasses and therefore, more air to the fire. Inadequate airflow causes the fire to burn at a lower temperature. Hotter burning fires are best because the hotter air passes through the flue more quickly and prevents the condensation of creosote in the flue.