A chimney cap is the metal cover, usually stainless steel or copper, that sits on top of the flue opening to keep rain, snow, debris, and animals out while still letting smoke draft freely.
The cap mounts directly over the flue outlet, above the crown, and it's a separate piece from the crown even though people mix the two up. A good cap has mesh sides that let smoke escape while blocking birds, squirrels, and leaves from getting into the flue and building a nest or clog. Multi-flue chimneys sometimes get one cap per flue or a single cap that spans the whole top, depending on the flue layout.
An open flue with no cap lets rain run straight down the liner every time it storms, and up here that means freeze-thaw damage working on the liner and smoke chamber from the inside instead of just the outside. A cap also stops downdrafts and cuts down on the debris that collects in the smoke chamber over a wet mountain winter. Stainless steel and copper hold up to that kind of repeated wetting far better than lighter, painted metal, which is part of why we steer clients toward those materials on a replacement.
More masonry vocabulary from the glossary.
The services where this term comes up.
Chelo's Brick & Stone serves Hillsville, Galax, Wytheville, Fancy Gap, and Independence, VA. Call for a straight answer and a free on-site estimate.
