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Chimney caps: the cheapest part with the biggest job
A cap is the metal cover over the flue opening. A crown is the concrete around it. People swap the words, but the parts do different work: the crown sheds water off the masonry, the cap keeps rain, birds, raccoons, and embers out of the flue itself. An uncapped flue in this climate swallows gallons per storm, straight down the liner and into the smoke shelf, where the water mixes with creosote into an acid that eats mortar from the inside.
What we install
Stainless steel caps sized to the flue, mechanically fastened, with spark screens standard. Galvanized caps cost less at the register and rust through in a handful of Sound-side winters, so we do not stock them. Homes near Chambers Bay and Day Island get wind-rated mounting, because a cap that leaves in a windstorm takes its value with it and sometimes takes a gutter on the way down.
Animals and the empty flue
Every spring we pull nesting material out of uncapped flues. Birds favor them, raccoons treat wide masonry flues as ready-made dens, and both leave blockages that push smoke and carbon monoxide back into the house the first time the fireplace lights in fall. A screened cap ends the problem permanently for less than the cost of one nest removal.
Common questions
How do I know if my chimney has a cap?
Stand where you see the top of the stack. A metal cover with visible mesh sides means capped. A bare flue tile opening or a concrete top with an open hole means uncapped, and worth a call before the fall rains.
How long does a stainless cap last?
Decades. Stainless handles marine air and constant moisture without rusting through. The fastening and the screen get checked during routine sweeps, and the cap itself typically outlasts the roof.
Will a cap hurt my fireplace draft?
A properly sized cap does not restrict draft. An undersized cap or a screen clogged with creosote can, which is why cap condition is part of every sweep and inspection we do.