Chimney Repair in Geneva, IL
Tuckpointing, crown rebuilds, firebox work and chimney flashing — the repairs that stop water destroying a chimney from the inside out. We quote after we have seen it, never before.
- Insured & Bonded
- 19 years in the trade
- Photos of every finding
- Open 7 days, 7am–8pm
Water, not fire, is what kills most chimneys here
A chimney is a masonry tower standing above the roofline with no shelter, taking every freeze-thaw cycle an Illinois winter produces. Brick and mortar are porous. Water soaks in during a thaw, freezes overnight, expands by roughly nine percent, and pushes the material apart from the inside. Repeat that a few dozen times a winter for twenty years and mortar joints crumble, brick faces pop off in flakes, and the crown cracks.
Almost every chimney repair we do in Geneva traces back to water getting in somewhere it should not. Which is why the first job on a repair visit is not fixing anything — it is finding the entry point. Fixing the symptom while leaving the leak open just buys you a couple of seasons.
Chimney flashing: the leak everyone blames on the roof
What flashing actually is. Where the chimney passes through the roof there is a permanent gap between a rigid masonry structure and a roof deck that moves, flexes and settles. Flashing is the metal that bridges that gap. It is not one piece. Step flashing is a series of overlapping L-shaped metal pieces woven in with each course of shingles up the sides. Counter flashing is a second layer, its top edge cut into a groove in the mortar joint, folded down over the step flashing so water running down the brick is thrown outward rather than behind. Done properly the two layers overlap like scales and there is no straight path in.
Why it fails. Three ways, in order of how often we see them. First, the mortar groove holding the counter flashing erodes, the sealant in it dries and shrinks, and the top edge lifts away from the brick — now water runs behind the metal instead of over it. Second, the metal itself corrodes or fatigues; aluminium against damp mortar corrodes faster than people expect, and decades of thermal movement work fasteners loose. Third — and this is the big one on houses that have been re-roofed — a roofer reused old flashing, or skipped the counter flashing entirely and ran a thick bead of roofing tar around the joint instead. Tar is not flashing. It looks like a repair for about two years, then it cracks, and because it is opaque and black you cannot see that it has failed.
How you know it is the flashing. A brown stain on the ceiling beside the chimney rather than directly under it. Damp or dark staining on the chimney breast in an upstairs room or the attic. Water appearing after wind-driven rain from one particular direction but not after gentle rain. Rusty streaks on the metal at the roofline. If you can get into the attic during a downpour with a torch, you can often watch it come in.
Re-seal, reflash, or leave it. If the metal is sound and only the mortar groove and sealant have failed, we rake the groove out properly and re-bed the counter flashing with fresh sealant. That is a genuine repair and it lasts. If the metal is corroded, fatigued, or was never installed as a two-layer system, sealing it again is a waste of your money — it has to come off and be reflashed. As for materials: aluminium is cheap and common, copper costs more and outlives the roof, and lead-coated copper is what we would use on a chimney we expected to still be standing in fifty years. What we will not do is run a bead of tar around a failed joint and call it fixed.
When it is genuinely the roof. Sometimes it is. Failed shingles above the chimney, a cracked valley, or an ice dam backing water up under the courses will all produce a stain in roughly the same place. We will tell you when that is what we are looking at, and we will not invent chimney work to fill the visit.
The other repairs we do most
Tuckpointing
Raking out failed mortar joints to a proper depth and repacking them. Done shallow it falls out in two winters; done to depth with the right mortar it lasts decades.
Crown repair and rebuild
The concrete slab on top. It should overhang the brick with a drip edge and slope water off. Most builder crowns are a thin skim of mortar and crack early.
Firebox rebuilds
Cracked or missing firebrick and eroded refractory mortar. A firebox with open joints lets heat reach the surrounding masonry.
Waterproofing
Breathable masonry sealer that stops liquid water entering while still letting vapour escape. Never use a non-breathable sealer on a chimney.
Spalled brick replacement
Where faces have popped off and the brick is crumbling, individual units get cut out and replaced.
Smoke chamber parging
Smoothing a rough corbelled smoke chamber so it drafts properly and collects less creosote.
How we price repairs
After an inspection, not before. Pricing masonry from a phone description is guesswork, and guesswork either overcharges you or turns into an awkward conversation halfway through the job. We look, photograph, explain, and then quote a number that does not move.
Starting prices for repair work are published on the pricing page so you have a sense of scale before you call. If the inspection shows the liner rather than the masonry is the problem, that is relining.
Stain on the ceiling near the chimney?
Get it looked at before the next freeze-thaw cycle makes it bigger. Seven days a week, 7am to 8pm.
Chimney repair questions
How do I know if my leak is the chimney or the roof?
Position and timing. A stain beside the chimney breast rather than directly under a roof plane, appearing after wind-driven rain from one direction, usually points at flashing or the crown. We check all the chimney entry points first and tell you honestly when the answer is a roofer.
What is tuckpointing and do I need it?
Raking out deteriorated mortar joints and repacking them with fresh mortar. You need it when joints have receded noticeably, when mortar crumbles under a key, or when you can see daylight or gaps. Done to proper depth it lasts decades; done as a shallow smear it fails in a couple of winters.
Can a cracked chimney crown be repaired or does it need replacing?
Depends on the cracks. Fine surface cracking can be resurfaced with a flexible crown coating. Structural cracks wider than a pencil line, or a crown that has broken into pieces, needs cutting off and recasting properly with an overhang and a drip edge.
Is chimney flashing repair something a roofer should do?
Either trade can, but the failure is usually at the masonry interface — the mortar groove holding the counter flashing — which is chimney work. The common bad outcome is a roofer sealing over old flashing with tar rather than reflashing properly.
How long does chimney repair take?
A flashing re-seal or small tuckpointing job is often a single day. A crown rebuild is typically one to two days plus cure time. Larger rebuilds run longer and are weather dependent, since you cannot lay masonry in a hard freeze.
Can you repair a chimney in winter?
Sweeping, inspection and interior work, yes, all year. Masonry is different — mortar will not cure properly below about 40 degrees, so exterior rebuilds and tuckpointing get scheduled for milder weather. We will tell you if something genuinely cannot wait.
Should I waterproof my chimney?
Often worth it once the masonry is sound, using a breathable siloxane-type sealer made for chimneys. Critically, it must let vapour out. A non-breathable sealer traps moisture inside the brick and makes freeze-thaw damage worse, not better.
My chimney has white chalky streaks. What is that?
Efflorescence — dissolved salts carried to the surface as water moves through the masonry and evaporates. The stains themselves are cosmetic, but they are proof that water is moving through the structure, so treat them as a symptom worth investigating.
Written by Rick Lee, owner of Zenith Chimney Service in Geneva, Illinois. 19 years in the chimney trade.
Published August 27, 2026