Somebody handed you a report that says the crown is cracked, or the cap is missing, or both. Then you looked up at your roof from the driveway and could not tell which part of the chimney anybody meant.
The two words get swapped constantly, including by people who work on houses for a living. Two different parts, two different materials, two different repairs.
A chimney crown is the sloped masonry slab that seals the top of the chimney, around the flue. A chimney cap is the metal lid that covers the flue opening itself. A cracked crown sends water down into the brick below it, and a crack that keeps running down the brick is movement, not a crown problem.
Crown, cap, chase cover: what each one is
The crown is concrete, and it is the part that sheds rain
The crown is a slab poured across the top of the brick and sloped away from the flue tile, so rain runs off the edge rather than soaking into the masonry. The International Residential Code describes it as a concrete, metal or stone cap, sloped to shed water, with a drip edge and a caulked bond break around any flue liners, installed per ASTM C1283 (IRC R1003.9.1). The specs the masonry trade works to add two more numbers: at least 2 inches of thickness at the outer edge, and at least a 2 inch overhang past the face of the brick so water drips clear instead of running back down the wall.
Part of the confusion starts right there. The building code calls that concrete slab a chimney cap. Most chimney companies, most inspectors and most homeowners call it the crown.
The cap is metal, and it covers the hole
The cap most people mean is the metal lid over the flue opening, usually stainless or copper, with mesh around the sides and a small roof over the top. A cap keeps rain, leaves, birds and squirrels out of the flue while letting smoke out.
A crown can be perfect and the cap still be missing. Wind takes them off. Some chimneys were built without one.
The chase cover belongs to a different kind of chimney
Where the chimney is a framed box with brick or siding wrapped around a manufactured firebox, the top is not a poured crown at all. A sheet metal pan called a chase cover sits over the whole opening. Galvanized ones rust from the middle out and leave orange streaks down the brick, which is usually the first thing a homeowner notices.
Which one is cracked, the cap or the crown?
You can sort most of this out from the yard with a phone camera or a pair of binoculars.
Gray concrete across the top of the brick with fine cracks spreading out from the flue tile is a crown. Orange staining running down the brick from a metal pan at the top is a rusting chase cover. Bare flue tile sticking up with nothing over the opening is a missing cap.
Which one you have also tells you what kind of chimney you own. A solid masonry chimney gets a poured crown, a manufactured one gets a chase cover, and the owner of Anglin's uses the same distinction when he is working out how a chimney is moving: "if there's a true masonry fireplace with your Terra Cotta flue liners, all of your filled brick, real dampers, and real fire brick, it leans from top to bottom."
What a cracked chimney crown actually leads to
Start with the reassuring part. A hairline crack in a crown, by itself, is a maintenance item on the top of your chimney. Nothing about it means your foundation moved.
What it does is let water in where nothing was meant to get in. Rain runs into the crack, soaks the top courses of brick, and sits in the masonry through the cold nights metro Atlanta gets every winter. Wet brick that freezes pushes its own face off, which masons call spalling, and the mortar joints open up behind it.
Give a cracked crown a few seasons and the damage shows up lower than the crack did: crumbling joints at the top of the stack, a brick face flaking off, sometimes a stain on the ceiling in the room below. Repointing three courses of brick is a small job. Rebuilding the top of a chimney is not.
What a missing chimney cap lets in
A missing cap points the water somewhere else, straight down the flue.
Rain lands on the damper and the smoke shelf, rusts the damper until it will not close, and works on the mortar joints inside the flue. Animals are the other half of it. Birds and squirrels nest in an open flue, the nest blocks the draft, and the first sign is usually smoke coming back into the room or a smell in the house on a warm day.
None of that is structural either. A cap is a part you buy and somebody installs, and it is one of the least expensive things on a chimney.
When the crack at the top is not a crown problem at all
Here is the test worth doing before you spend anything.
Follow the crack down. A crack that lives in the concrete crown and stops where the brick begins is a crown problem. A crack that starts at the crown and keeps running down through the brick joints, course after course, is telling you the chimney itself has moved. Brick separating from the house, a gap at the wall you can see from the yard, or a stack that tilts in above the roofline are all the same message.
Anglin's hears it in the words people use on the phone. As the owner puts it, "it's either chimney cracking, chimney leaning, chimney pulling." He says the calls that start with a report are just as common: "my inspection report came back, and I got a crack in my chimney." That one arrives through real estate agents constantly, usually with a closing date attached.
If the crack runs, the reason is almost never the bricklaying. Metro Atlanta soil is dense red clay, and the USDA rates it low for shrinking and swelling, so it is not heaving your chimney around with the seasons. Water is what moves a chimney here: a downspout emptying beside it, a grade that falls back toward the house, runoff that has been washing the same patch of a sloped lot for twenty years. Why is my chimney leaning walks through where the lean starts and what each kind means.
Who to call for a cap, a crown or the brick under both
Anglin's will tell you this before you ask. Caps, liners, flues and the leaks around flashing are a sweep's work or a roofer's, and this company does not take them on. The owner draws the line in one sentence: "we're professionals at what we do, your roofer is your professional."
What Anglin's owns is the structure and the masonry: straightening a chimney that has moved, stabilizing the footing under it, and putting the brick back. The last part of every job is the part homeowners actually see, and the owner describes it as "the cosmetics, to get the brick matching, the mortar matching, the aging, the tuck pointing process."
So the honest routing is simple. Cracked crown with sound brick underneath, call a sweep or a mason who does crowns. No cap over the flue, call a sweep. Crack running down the brick, a gap at the house, or a stack leaning above the roof, that is what the chimney repair crew does, and has done in Atlanta since 1930.
Frequently asked questions about chimney caps and crowns
Does Anglin's install chimney caps or rebuild crowns?
No. Anglin's handles structural chimney work and the masonry that goes with it, which means straightening a chimney that has moved, stabilizing the footing, and repairing brick and mortar. Caps, liners, flues and flashing leaks are work for a sweep or a roofer, and the company says so up front rather than taking the job.
Is a chase cover the same thing as a chimney crown?
No. A crown is poured concrete on a solid masonry chimney, and a chase cover is a sheet metal pan on a framed chimney built around a manufactured firebox. Rust streaks running down the brick usually mean a chase cover, while fine cracks in a gray slab up top mean a crown.
Can a cracked crown be sealed, or does it have to be rebuilt?
Hairline cracks are often bridged with a flexible crown sealant, while a crown that has broken into pieces or lost its overhang usually gets recast. A crown that is too thin or was built from mortar instead of concrete tends to crack again after a patch, which is why the 2 inch thickness and 2 inch overhang in the trade specs matter.
Do I still need a cap if nobody ever uses the fireplace?
Yes, arguably more. An unused flue is an open pipe into your house that collects rain, nests and debris all year, and the damper below it rusts open with nothing to stop the draft. A cap is one of the cheapest parts on the whole chimney.
Will a home inspector write up a cracked chimney crown?
Usually, yes, and cracked crowns show up on inspection reports constantly during a sale. An inspector notes the crack and recommends further evaluation, which is why so many chimney calls arrive with a closing date attached. Whether it becomes a negotiating item depends on whether the crack stops at the crown or keeps going down the brick.
How high above the roof is a chimney supposed to be?
The residential code sets the termination: a chimney extends at least 2 feet higher than any portion of the building within 10 feet, and not less than 3 feet above the point where it passes through the roof. A chimney that is short for its roof drafts poorly. A chimney that has settled or tilted is a separate question from how tall it was built.
A homeowner on the mortar work
Worth hearing from someone whose chimney needed both the structure and the brick put right:
"Fast, professional. Did an excellent job on getting a leaning chimney resolved and repaired cracked mortar on some bricks."
Chris Kilroy, 5 stars
Find out whether the crack stops at the top
You should not have to guess at this from the driveway, and you should not pay for structural work you do not need.
A mason can stand in your yard, look at where the crack starts and where it ends, and tell you plainly whether the top of your chimney needs a sweep or the chimney itself has moved. Anglin's has been repairing Atlanta chimneys since 1930, and a chimney call reaches one of the owners the same day.
Call 770-422-2924 for a free look.