Your chimney takes more weather than anything else on the house. It stands above the roofline with no shelter, exposed on four sides, and it gets hit from the inside too, because combustion pushes warm, damp, acidic air through the structure. That is why chimneys are usually the first masonry on a house to fail, often by decades.
Start with the crown
The crown is the concrete slab across the top. Its whole job is to throw water clear of the brick below. A proper crown is poured concrete, several inches thick, sloped, and overhanging the brick with a drip edge so water drips free rather than running down the face.
What a lot of Chicago-area chimneys actually have is a thin mortar wash troweled flush with the brick. It cracks within a handful of winters, and then every rainstorm is feeding water directly into the top of the stack.
Then the flashing
Where the chimney passes through the roof there should be two layers of metal: step flashing woven into the shingles, and counter flashing let into a cut in the mortar joints and sealed. Done right, it lasts as long as the roof.
Done wrong, which usually means a bead of roof tar over the gap, it lasts about two years and then quietly leaks into the roof deck. If you have a stain on a bedroom ceiling near the chimney, this is where to look first.
Rebuilding above the roofline
When the mortar has failed throughout the exposed section, or the stack has started to lean, rebuilding from the roofline up is the right repair. We take it down to sound masonry, salvage the brick where it is reusable, and rebuild it plumb with a correct mortar mix, a poured crown, new flashing and a cap.
We will always tell you when a crown and flashing would do the job instead. A rebuild is a real expense, and most chimneys we look at do not need one yet.
Signs you need this work
- Cracked or missing concrete crown at the top
- Water stains on the ceiling near the chimney
- Loose or fallen brick in the yard after a storm
- A chimney that visibly leans
- Rusted, lifting or tar-patched flashing at the roofline
- White staining down the chimney face
- Damp or musty smell in the fireplace
What's included
- Inspection from the roof, with photos you can actually see
- New poured concrete crown with proper overhang and drip edge
- Rebuilding above the roofline using matched brick
- New step and counter flashing, properly let into the mortar joints
- Chimney cap installation to keep rain and animals out
- Water-repellent treatment where appropriate
- Coordination with your roofer when the roof is involved
How we do it
- 1
Roof-level inspection
We get up there and photograph the crown, flashing, brick and cap so you can see exactly what we are talking about.
- 2
Honest scope
Plenty of chimneys need a crown and flashing, not a rebuild. We will tell you which one yours is.
- 3
Tear-down and rebuild
Failed masonry comes down to sound material, then goes back up plumb with matched brick and correct mortar.
- 4
Crown, cap and flashing
A poured crown with a real overhang, new counter flashing cut into the joints, and a cap on top.
Common questions
How do I know if I need a rebuild or just repair?
If the damage is confined to the crown, the flashing and the top few courses, a partial rebuild or repair is usually enough. If mortar has failed throughout or the stack is leaning, it needs rebuilding from the roofline.
Why do chimneys fail before the rest of the house?
They are exposed on all four sides, they get no shelter from the roof, and they take the full freeze-thaw cycle. Combustion also pushes moisture and acidic condensate through the structure from the inside.
What is a chimney crown?
The sloped concrete slab on top of the chimney. It sheds water away from the brick and the flue. A proper crown overhangs the brick with a drip edge. A thin mortar wash smeared on top, which is what many chimneys have, cracks within a few years.
My chimney leaks but the brick looks fine.
Then it is almost certainly the flashing or the crown. Flashing that has been tarred over rather than replaced is the single most common source of chimney leaks we find.
Do you sweep chimneys or line flues?
We are masons, so we handle the structure: brick, crown, flashing and caps. For flue liners and sweeping we will point you to a certified chimney sweep.