Chimney caps and crowns in Geneva, IL
Stainless caps sized to your flue, crown resurfacing where it will hold, and full recasting where it will not.
- Insured & Bonded
- 19 years in the trade
- Three brothers, one crew
- Open 7 days, 7am–8pm
The crown and the cap are different parts. The crown is the concrete slab covering the top course of brick, sealing the masonry around the flue opening. The cap is the metal lid and mesh over the flue opening itself. The crown keeps water out of the brickwork; the cap keeps rain, animals and embers out of the flue. A chimney with no cap is an open pipe into the house.
Smoke coming into the room, flames or roaring in the flue, or a carbon monoxide alarm sounding? Get everyone out and call the fire service first, then call us. We put these calls to the front of the queue.
What a missing cap actually costs you
Rain goes straight down the flue onto the damper and smoke shelf. The damper rusts, first stiffening and then seizing solid. The masonry soaks from the inside where it never dries properly. Mixed with creosote, that water forms an acidic sludge that attacks mortar joints from within the flue — damage you cannot see from the room or from the ground.
Animals move in. Squirrels, raccoons and chimney swifts nest in open flues every spring. A nest is a total blockage, and a blocked flue pushes combustion gases back into the house. With a wood fire you get smoke as a warning. With a gas appliance you get carbon monoxide and no warning at all.
Embers land on your roof. The mesh screen on a cap is a spark arrestor. On any wood-burning system under a shingle roof that is its own justification.
Downdraft. A correctly sized cap can genuinely reduce the wind-driven gust that pushes a puff of smoke back into the room on a blustery evening. It is not a cure for every draft problem, but on exposed sites it helps.
What a proper crown has
Cast concrete, not mortar. Concrete is a structural weather-resistant material; mortar is a bedding compound and was never intended to be a roof.
A slope away from the flue so water runs off rather than sitting.
An overhang past the face of the brick by an inch or two, with a drip edge cut into the underside. This is the detail almost everyone omits and it is the important one — without it, runoff clings to the underside and runs straight down the face of the brickwork every time it rains.
An expansion joint around the flue tile. Tile and concrete expand at different rates, and without a flexible joint the crown cracks around the flue as a matter of course.
What most houses got instead is a thin skim of ordinary mortar, flush with the brick, no overhang, no drip edge, no expansion joint. Quick, cheap, fine on handover day, cracked within a few years.
Resurface or recast
Fine surface cracking can be resurfaced with a flexible crown coating that stays elastic through freeze-thaw. That is a genuinely good outcome for modest money, and where it is the right call we say so rather than sell a rebuild.
Structural cracks wider than a pencil line, sections that have broken away, or a crown that has separated from the flue tile need cutting off and recasting properly — with the overhang, drip edge and expansion joint that should have been there originally.
Telling those apart is a judgement made from photographs on the roof, not from the ground.
Choosing a cap
Stainless steel for durability, or copper where appearance matters and the budget allows. Galvanised is cheapest and rusts out fastest, which on an Illinois roof means replacing it again sooner than you would like.
On a prefabricated metal chimney the cap is often part of a manufacturer-specified termination assembly rather than a generic accessory. Fitting a generic cap to a listed system can void the listing and frequently does not seal correctly.
Gas flues need caps too. The flue is still open to rain and to nesting animals, and a blocked gas flue is the more dangerous of the two because there is no smoke to warn you.
One timing note: if there is an active nest with young in it, some species are legally protected and capping has to wait until they fledge. We will give you a realistic date rather than sealing something in.
Not sure whether you have a cap?
Binoculars from the ground will usually tell you. Or call and we will check.
Cap and crown questions
What is the difference between a crown and a cap?
The crown is the concrete slab covering the top of the brickwork. The cap is the metal lid over the flue opening. A chimney needs both.
Can I see crown damage from the ground?
Often yes, with binoculars. Visible cracks or missing sections are enough to justify a call. Do not go up on the roof to check.
What is a drip edge and why does it matter?
A groove cut into the underside of the crown overhang. It makes runoff drop clear of the brickwork instead of running down the face. Most crowns lack it.
Is a crown coating a permanent fix?
For fine surface cracking it is a durable repair that stays flexible through freeze-thaw. It is not a fix for structural cracks or a broken crown.
Will a cap stop my fireplace smoking?
Sometimes. If smoke rolls back on windy days a correctly sized cap can help by disrupting downdraft. If it smokes in still conditions the cause is elsewhere.
Do gas fireplaces need a cap?
Yes. The flue is still exposed to rain and nesting animals, and a blocked gas flue is more dangerous than a blocked wood one.
There is an animal in the chimney. Can you cap it now?
Only once it is empty. Sealing an animal in is inhumane and leaves you with a worse problem, and some nesting birds are legally protected.
How are caps and crown work priced?
Caps and crown resurfacing both have published starting prices, listed in one place with everything else. See the pricing page.
Other things we do
All eight services come from the same three people.
Chimney sweeping · Chimney inspection · Chimney repair · Chimney relining · Gas fireplace service
Written by Rick Lee, owner of Zenith Chimney Service, Geneva IL. Published September 4, 2026.