The cap is the small, easily overlooked part of a chimney that quietly prevents some of its most expensive problems. An open flue is an open invitation for rain and snow to pour straight down onto the damper and the smoke shelf, for sparks to drift onto the roof, and for squirrels, raccoons, and nesting birds to take up residence in the one shaft that is supposed to carry smoke out. Boston Chimney Sweep installs chimney caps across the city in stainless steel and copper, sized to your particular flue, fitted with spark-arrestor mesh, and secured to stay put through a New England nor'easter. It is one of the least costly upgrades a chimney can get and one of the highest in payback.
- Stainless steel and copper caps to suit the chimney
- Sized to your exact flue, not a generic fit
- Spark-arrestor mesh to keep embers off the roof
- Keeps rain, snow, and animals out of the flue
- Secured to hold through New England wind
- Multi-flue caps for shared city chimney stacks
The quiet damage an open flue lets in
A chimney without a cap is a vertical drain pointed straight into the heart of the structure, and in a city with Boston's rain and snowfall that matters more than people realize. Every storm sends water down the open flue onto the smoke shelf and the damper, where it rusts the metal, pools, and soaks into the masonry from the inside, accelerating exactly the kind of deterioration that leads to cracked tile and a leaking chimney. Snow does the same job more slowly, packing into the flue and melting in stages so the wetting goes on for days after the storm has passed. A cap turns that open drain into a covered, vented opening that still lets smoke out while keeping the weather from coming in.
Animals are the other reason an uncapped flue causes trouble. A warm chimney is prime real estate for squirrels, raccoons, and chimney swifts, and a flue that fills with a nest is a flue that will not draft, which pushes smoke and carbon monoxide back into the house the moment you light a fire. Removing a nest is unpleasant, sometimes dangerous, and entirely avoidable. The mesh on a properly fitted cap keeps the animals out before they ever get in, and it doubles as a spark arrestor, catching the embers that a wood fire throws up the flue before they can land on a Boston roof or a neighbor's.
Fitting a cap that actually fits and stays
A cap only does its job if it is sized and secured correctly, which is why a generic cap jammed onto a flue is rarely worth the trouble. We measure the actual flue, or every flue on a shared stack, and fit a cap matched to it, because a cap that is too tight restricts the draft and a cap that is too loose comes off in the first hard wind. On Boston's tall city chimneys, exposed to the wind that funnels between buildings and the gusts that come with a coastal storm, the fastening matters as much as the fit. We anchor caps to hold, and we use stainless steel or copper rather than a thin galvanized cap that will rust through in a few seasons of New England weather.
Many older Boston homes have a single chimney stack carrying two or more flues, the fireplace, the furnace, an old gas line, and these call for a multi-flue cap that covers the whole top with one well-built enclosure rather than a cluster of mismatched single caps. A multi-flue cap also lets us address the crown beneath it at the same time, since the two work together to keep the top of the chimney watertight. We talk through the right cap for your particular chimney, in the metal that fits your budget and how long you intend to stay, and we leave you with an opening that vents freely and seals against everything it should.
A small cost that prevents large ones
Of all the work a chimney can need, a cap is among the best values, precisely because it heads off the slow, costly damage that nobody notices until it is serious. The price of a good cap is a fraction of what it costs to repair the rusted damper, the water-soaked masonry, or the cracked crown that an open flue invites, and it is a tiny fraction of removing an animal nest and repairing the fire risk a blocked flue creates. A cap is silent insurance for the whole top of the chimney, and on a Boston home exposed to a full New England year it pays for itself many times over.
If your chimney has no cap, or the cap it has is rusted, crushed, or hanging loose, the fix is usually quick and inexpensive, and it is one of the easiest ways to extend the life of everything below it. Cap work also fits naturally alongside a crown repair or a sweep, and lining the two up together often makes good sense, since the crew is already on the roof and the top of the chimney is open to work on. We will look at the top of your chimney, tell you honestly what it needs, and put a straight price in writing, with no pressure to add work the chimney does not actually require.
Every part of the chimney, handled
A chimney is a system, so chimney cap installation rarely stands alone, it connects to creosote removal, chimney condition assessment, chimney repair, chimney liner replacement, chimney repointing, and our crew handles all of it under one roof. We bring the same service to Cambridge chimney cap installation, Somerville chimney cap installation, Chimney Cap Installation in Brookline, Chimney Cap Installation in Quincy and everywhere else across the Boston area.
If you searched for local chimney service, you have reached a local crew, call 508-296-8030 any time. For background, read Old Clay-Tile Flues in Boston, MA Homes: When to Reline on our blog, or head back to our Boston home page to see everything we do.