If we had to name the single part that fails first on an older chimney, it would be the crown. AM Chimney Sweep repairs and replaces chimney crowns in Clifton, along with cleaning, inspection and other chimney repairs, and this page explains what a crown does and how to judge the condition of yours.
What the crown is
The crown is the slab that closes the top of the chimney around the flue. Its job is to shed rain away from the opening and off the edges of the brickwork. It is not the cap, which is the metal cover over the flue itself. A chimney needs both.
Why so many Clifton crowns are due
Census Bureau estimates show that roughly two-thirds of Clifton’s homes were built before 1960. On houses of that age the original crown was frequently nothing more than a thin layer of leftover bricklaying mortar smoothed over the top. Mortar is the wrong material for the job. It shrinks, cracks and lets water through, and after sixty-plus New Jersey winters very few of those original crowns are still intact.
Source: U.S. Census Bureau, American Community Survey 2020–2024 five-year estimates.
How a small crack becomes a large repair
Water enters a hairline crack, freezes, expands and opens the crack a little further. The cycle repeats many times each winter. Once water is getting past the crown it runs down inside the chimney, where it soaks the brick from the inside, rusts the damper, loosens flue tiles and eventually shows up as a stain on a ceiling or wall. A crown repair done in time is a modest job. The damage underneath a neglected one is not.
What you can see from the ground
- Visible cracks or missing pieces along the top edge
- Plants or moss growing out of the top of the chimney
- Bits of cement on the roof or in the gutter below
- Dark, damp-looking brick in the top few courses after the rest has dried
- A flue tile that looks loose or sits crooked in the crown
Binoculars help. Anything closer than that is a job for someone equipped to be on the roof.
Repair or replace?
Repair
When the crown is solid and the cracks are fine, it can be cleaned and resurfaced with a flexible, waterproof crown coating that bridges the cracks and seals the surface.
Replace
When the crown is crumbling, has chunks missing, is loose on the brick, or was never more than a skim of mortar, it should be removed and rebuilt. A properly built crown is thicker, slopes away from the flue, extends past the face of the brick so water drips clear of the wall, and leaves a sealed gap around the flue tile so the tile can expand when hot.
We tell you which applies after looking at it, with photos from the roof. More detail is on our crown repair and replacement page.
Questions from Clifton homeowners
Can crown work be done in winter?
Cement and coatings need moderate temperatures to cure. Spring through fall is the practical season, which is a good reason not to wait until the first freeze.
I own a two-family. Does each side need its own repair?
A shared chimney has one crown covering all of its flues, so it is one repair. More than a quarter of Clifton homes are in two- to four-family buildings, and this question comes up often.
Will a new cap fix a leaking crown?
No. A cap keeps rain out of the flue opening. It does nothing for cracks in the slab around it, unless it is a full-width cap designed to cover the entire top.
Get your crown checked
Call (862) 225-6529 or send a request. A crown check is part of every chimney inspection we do, and we also handle repointing if the top courses have already suffered. For examples, see our crown projects in Montclair and East Brunswick, or all of Our Work.