The Chimney Cap | Best Pick Reports
The chimney cap is a device usually made of stainless steel or copper, which is used to protect the chimney from invasion by pests. The warmth and shelter provided by uncapped chimneys can attract birds, squirrels, raccoons, and other furry pests who may nest in the chimney space. This can lead to inefficiency in the fireplace, and the presence of the nesting materials poses a fire hazard.
Another advantage of the chimney cap is that they also shield the top of the chimney from ice accumulations and keep rain water out of the flue, which will extend its life.
Lastly, chimney caps are important because they contain fire sparks within the chimney and keep stray embers from igniting the roof or flying down into the yard.
In particular, metal chimneys need to have a chimney cap. Metals chimneys are fabricated with two or three layers of metal with insulation between each; a chimney cap prevents water and moisture from accumulating between the layers, reducing the chance for premature failure of the chimney. Most metal chimneys are sold and installed with a chimney cap.
A masonry chimney may or may not require a chimney cap. There are distinct advantages, including protection of the cement crown at the top of a masonry chimney as well as an increase in the chimney’s draft in areas where there is constant wind. However, soot can collect on the chimney cap and run down the side of the structure which can discolor the brick, though this problem is most prominent with the use of green wood or older wood stoves. Sizing a chimney cap for a masonry chimney requires professional measurement.
There are many different types of chimney caps: draft-increasing, H-pot, integral damper, top-mount, and many others. To determine the best type of cap, a homeowner should consult a chimney and fireplace professional.