Stainless caps and spark arrestors, measured to your flue and fitted to meet California code. The cheapest thing on a chimney and the one doing the most work.
A chimney cap is the covered metal housing that sits on top of the flue. It keeps rain, animals and debris out of the chimney, and the mesh around its sides stops embers leaving the flue and landing on your roof.
People treat it as an accessory. An open flue is a hole in the top of your house, roughly the size of a small window, pointing straight up. Everything that lands on the roof can go down it.
Ask a chimney sweep what they pull out of uncapped flues and you will get a list. Nests. Leaves. Dead animals. Tennis balls. Water, most of all, which soaks into the masonry, freezes nothing in Los Angeles but rusts the damper and rots the mortar from the inside.
And in California the mesh is not optional. Any chimney serving a solid-fuel fireplace needs an approved spark arrestor. More on what approved means below.
The big one in Los Angeles, and the one people least expect. Rain going straight down an open flue soaks the smoke chamber and rusts the damper. It shows up months later as a stain on the ceiling.
The mesh is a spark arrestor. It catches hot fragments before they leave the flue, which matters on any roof and matters a great deal on a hillside one.
Birds, raccoons and squirrels all treat an open flue as available housing. Getting a nest out is a bigger job than fitting the cap that would have prevented it.
A cap with the right hood height shields the flue from wind blowing across the roof, which reduces the gusts that push smoke back down into the room.
This is where most caps sold online fall down. California sets measurable criteria for spark arrestors, and a cap that looks right can still fail them. The current Building Code language covers four things.
That opening range is why five eighths inch mesh became the default on California caps. It will not pass a half inch sphere, so it satisfies the upper limit while staying open enough to draft. Three quarter inch mesh, which is standard in most of the country, does not.
In the county's designated wildfire risk areas there is a further requirement for heavy wire mesh with openings not exceeding half an inch. Plenty of hillside addresses across the Westside and the Valley fall inside those areas.
Code editions and local amendments change. We work to the version in force for your address and confirm it before ordering anything.
Caps are exposed to everything the roof gets and nobody looks at them. Most of the ones we replace failed years before anyone noticed.
Flues come in more shapes than people expect. Square, rectangular, round, oval, and multiple flues sharing one crown. Guessing the size is how you end up with a cap that rattles or does not seat.
Flue dimensions, how far it protrudes above the crown, and whether the crown itself is sound enough to mount to.
Often the cap is the visible problem and the crown underneath is the real one. You get told about both, and a price for each.
Single flue or multi flue, stainless or copper, standard or a taller hood if downdraft is the issue you are trying to solve.
Mounted to the flue tile or the crown depending on the build, sealed where it needs sealing, and left square.
Before and after from the roof, since you are unlikely to go up and look yourself.
Same chimney, same angle. A cap is a small part that changes what the top of the chimney is doing.
A spark arrestor is. The Building Code requires an approved spark arrestor on any chimney serving a fireplace or appliance burning solid fuel, and it sets specific criteria for mesh size, material and open area. Most caps sold here combine the rain hood and the arrestor in one unit.
Five eighths of an inch is the practical answer in California. The code says the openings must not pass a half inch sphere, and five eighths mesh clears that while still drafting properly. The three quarter inch mesh sold as standard in most states does not.
Flue size and material set most of it. After that it depends how many flues share the crown and how hard the roof is to work on. A single stainless cap on an easy roof is a different job to a multi-flue cover on a steep hillside pitch. We measure, then quote.
Stainless, particularly anywhere near the coast. Galvanized costs less and rusts sooner, and salt air accelerates that considerably. Replacing a cheap cap twice costs more than fitting a good one once.
Physically, sometimes. The parts people get wrong are measuring an oval or rectangular flue, getting a mesh that actually meets code, and working safely on a pitched roof. A cap that does not seat properly can lift in wind, and one with the wrong mesh can restrict the draft.
Sometimes, if wind across the roof is the cause. A taller hood shields the flue and reduces downdraft. But smoke coming back can also mean a blockage, a flue sized wrong for the firebox, or a damper problem, so we check before promising a cap will solve it.
A quality stainless cap should last many years. Galvanized is shorter, and shorter again near the ocean. We check the condition on every sweep and inspection, so you hear about it while it is still a small job.
We measure the flue, check the crown underneath it, and fit a cap that meets the code for your address. Appointments are usually available the same week.
