What Chimney Crown Repair in Flower Mound Fixes
The chimney crown is the concrete slab across the top of a masonry chimney. It covers the bricks from the outside edge to the flue tile and is supposed to shed rain like a small roof. When it cracks, water runs straight into the brick and mortar below it, and from there into the firebox, the ceiling and the wall. Flower Mound Chimney Sweep Professionals repairs crowns on masonry chimneys across Flower Mound, Lewisville and Southlake.
A good crown has four things: at least 2 inches of thickness at the edge, a slope away from the flue, an overhang of about 2 inches past the brick with a drip edge cut under it, and a bond break (a gap with sealant) around the flue tile so the tile can expand when it heats. The Brick Industry Association describes this design in its technical notes on residential chimneys. Most crowns we see in Flower Mound have none of it. They are a thin wash of mortar troweled flat against the flue, and they crack.
Signs Your Chimney Crown Needs Repair
- Cracks across the top of the chimney you can see from the yard with binoculars
- Chunks of concrete or mortar in the gutter or on the roof below the chimney
- A dark water line on the brick just under the crown after rain
- White powder (efflorescence) on the top few courses of brick
- Flaking or popped brick faces near the top
- Water in the firebox or rust on the damper with no cap problem
- A chimney cap that wobbles because the crown under it is loose
Two of these together usually mean the crown has been leaking for a while and the tuckpointing below it should be checked at the same time.
Three Ways We Repair a Crown
| Condition of the crown | Repair | What it involves |
|---|---|---|
| Sound, 2 inches thick, hairline cracks only | Crown coating | Clean, fill cracks, brush on a flexible elastomeric crown sealer, two coats |
| Cracks up to 1/4 inch, some chipping, still solid | Patch and coat | Cut out loose material, patch with crown repair mortar, add a bond break at the flue, coat the whole crown |
| Thin mortar wash, pieces missing or loose, water under it | Crown replacement | Remove the old crown, form a new one, pour reinforced concrete with slope, overhang and drip edge, cure, seal |
We tell you which row you are in with photos from the roof, and the written price covers that repair only. If the brick under the crown is also failing, that is a separate line on the estimate, never a surprise.
How a Chimney Crown Repair Visit Works
- Inspect. We go on the roof, photograph the crown, measure its thickness and check the flue tile, cap and the top courses of brick. A camera check of the flue shows whether water has already reached the inside.
- Quote. You get the photos and a written price on the same visit. Estimates are free.
- Repair. Coatings and patches take a half day. A new crown takes a day to form and pour plus cure time before the cap goes back on.
- Finish. We re-set or replace the cap, photograph the finished crown and send the after photos.
Crown work needs dry weather above 40 degrees. In Flower Mound that is most of the year, but we do schedule around spring storm fronts.
Why Crowns Fail Faster in North Texas
Flower Mound summers run over 100 degrees for weeks, and the sun cooks the top of the chimney all day. Concrete and mortar expand in the heat and shrink at night, and a thin crown cracks from that cycle alone. Spring hail chips the surface. Winter freezes are short but they happen, and water in a crack turns to ice and widens it. Most masonry chimneys here were built in the 1980s and 1990s, so the crowns are reaching the age where the cracks go all the way through.
Chimney Leak Repair
A cracked crown is the first thing we check on a chimney leak repair call, but it is not the only thing. Flashing, the cap and the brick itself can leak in the same way. If the stain on your ceiling is at the base of the chimney rather than inside the firebox, the flashing is the more likely cause, and we test both before we quote.
Chimney Waterproofing
After the crown is sealed, a breathable water repellent on the brick finishes the job. Chimney waterproofing keeps the masonry from soaking up rain while letting moisture inside escape. We apply it after crown and mortar repairs, once the masonry is dry.
Chimney Tuckpointing and Rebuilds
Water that has been coming through a cracked crown for years usually takes the top mortar joints with it. We check those joints on every crown visit and quote chimney tuckpointing if they need it. When the top courses of brick are loose or spalled, a partial chimney rebuild from the roofline up, with a new crown as part of it, is the honest fix. For everything else on the chimney, see our main chimney repair page.
Book Chimney Crown Repair in Flower Mound
Flower Mound Chimney Sweep Professionals is veteran-owned and based on Long Prairie Rd in Flower Mound 75028. We repair chimney crowns in Flower Mound, Lewisville, Southlake, Colleyville, Keller, Fort Worth and Collin County, 7 days a week from 7 AM to 8 PM. Call (817) 518-6131 or send the form on this page. You get roof photos, a free written estimate and a firm price before we start, and a new chimney cap can go on at the same visit.
