A chimney cap is a small, inexpensive part that does an outsized amount of work, and an open flue without one is an open invitation to every problem a chimney can have. Sullivan Chimney Sweep installs caps across the Far Northeast that are sized to the flue they protect, made of stainless steel that will not rust away in a season, and fitted so they actually stay put through a Philadelphia winter. A good cap keeps rain out of the flue, keeps birds and squirrels from nesting in it, keeps debris from blocking it, and keeps embers from drifting onto the roof, and it is one of the highest-value upgrades a chimney can get for the money.
- Cap sized to the actual flue, not a one-size-fits-all guess
- Stainless steel that holds up to the weather rather than rusting out
- Rain kept out of the flue and the masonry below it
- Birds, squirrels, and nesting debris shut out of the chimney
- Spark arrestor screen to keep embers off the roof
- Fitted to stay seated through wind, snow, and freeze-thaw
The four jobs a single cap quietly handles
A cap looks like a trivial piece of metal on top of the chimney, but it stands between the flue and four separate kinds of trouble. First, water. An open flue is a funnel that pours rain straight down into the chimney, where it rusts the damper, soaks the smoke chamber, and works at the masonry from the inside. Second, animals. An open flue is exactly the warm, sheltered shaft a bird or a squirrel wants for a nest, and a nest is both a fire hazard and a blockage that can push exhaust back into the house. Third, debris. Leaves and twigs collect in an open flue and choke the draft. Fourth, sparks. The screen on a cap keeps embers from a fire from drifting out onto a roof or the dry leaves in the gutter.
Add those up and the cap is doing the work of four different protections at once, for a fraction of what fixing any one of those problems would cost after the fact. A rusted-out damper, a flue full of nest, a masonry stack soaked from the top down, a roof fire from a stray ember, these are the expensive consequences a twenty-dollar idea, properly executed, heads off. It is hard to name another chimney part that returns as much for as little.
Why a cap fitted right outlasts a cap simply stuck on
Not every cap is equal, and a cheap one fitted carelessly is barely better than none. The cap has to be sized to the flue it covers, because one that is too small leaves gaps and one that is too large does not seat. It has to be made of a material that survives the weather, which is why we install stainless steel rather than the painted or galvanized caps that rust through and stain the masonry within a few years. And it has to be fastened so it stays put, because a cap that blows off in the first real Far Northeast windstorm has done you no good at all and leaves the flue open again.
We measure the flue, fit the right cap for it, and secure it to ride out the wind, the snow load, and the freeze and thaw that work loose anything that was not seated properly. On a chimney with more than one flue, which is common on the houses out here that vent a fireplace and a furnace through the same stack, each flue gets covered correctly rather than crammed under a single ill-fitting lid. The aim is a cap you can forget about because it is doing its job, not one you find in the yard after the next storm.
A cap that fits the whole chimney plan
A cap rarely lives alone on the list of what a chimney needs, and fitting one is often the moment to set a few small things right together. While we are up there installing it we are looking at the crown it sits on, the top courses of brick, and the flashing below, and if the crown is cracked or the upper joints have opened, we will tell you, because a new cap over a failing crown is solving the smaller problem first. Lining the work up sensibly spares you a second trip up the roof and gives the chimney a clean bill at the top all at once.
That said, a cap does not have to wait on anything. If your flue is sitting open because the old cap rusted off or was never there, that is worth closing before the next nesting season or the next hard rain, on its own, regardless of whatever else the chimney may eventually want. We will measure it, price it in writing, and fit it as its own job if that is all the chimney needs. Whichever way it goes, you get the honest recommendation rather than a bundle of work padded around a simple cap.
How this links to the rest of the work
A chimney is a system, so chimney cap installation rarely stands alone, it connects to flue cleaning, flue inspection, crown repair, a new chimney liner, chimney masonry repair, and our crew handles all of it under one roof. We bring the same service to Somerton chimney cap installation, Chimney Cap Installation in Bustleton, Chimney Cap Installation in Fox Chase, Chimney Cap Installation in Rhawnhurst and everywhere else across the Philadelphia area.
If you searched for a local chimney crew near you, you have reached a local crew, call 215-602-7627 any time. For background, read Chimney Flashing: Where the Stack Meets the Roof and the Leaks Begin on our blog, or head back to our Philadelphia home page to see everything we do.