We always ask a homeowner “Is your chimney cap safe” during out first visit. A chimney cap extends flue life and is important in the proper functioning of a fireplace.
A chimney cap should be installed, if not already in place. It will keep animals, rainwater, leaves and debris out of the chimney. When water, leaves, and debris mix with the soot behind the damper, an acidic slurry can form, which can destroy the firebrick mortar joints. The metal cap acts as a spark arrester, helping lit embers or sparks that travel up the chimney from landing on the roof, possibly catching it on fire.
A chimney cap can also help in preventing downdrafts. If the wind is blowing in a certain direction, it can introduce a downdraft, and if you don’t have a chimney cap and you’re using a wood-burning fireplace at the time, a wind-induced downdraft has the potential of blowing smoke back into your home. The flat-shaped top of a chimney cap is designed to help prevent wind-induced downdrafts.
Be aware this can be a dangerous job. Often the fireplace cap is located high above the highest point on your roof. It very well may be 3 stories off of the ground. If you are not comfortable climbing ladders and are afraid of heights, hire a professional to be safe for your family.
Before you start a fire each year, your chimney, flue, grate and cap should be inspected. Request a chimney cleaning as soon as possible in the season. You need to be sure your chimney cap is safe before you start a fire.