Case study: the summer smell that three sweeps could not fix
An illustrative, step-by-step look at how we diagnose and repair a recurring chimney problem — not a real customer, built to show the process.
The situation: a smell that came back every summer
Picture a two-storey brick home built in the 1970s near the Kankakee River, with a wood-burning fireplace used a dozen or so times each winter. Every summer, when the air conditioning ran, a sharp campfire-and-asphalt smell drifted out of the cold fireplace and into the living room. The homeowner had the flue swept two years running by another company, and each time the smell returned within weeks. By the time this illustrative call came in, they were ready to stop using the fireplace altogether.
The inspection: looking instead of guessing
Rather than sweep again and hope, the first step was a camera inspection of the full flue — the approach described on our chimney inspection page. Three things showed up. First, a band of hard, shiny stage-three creosote glaze about two thirds of the way up, the kind a standard brush skates over. Second, the top-sealing damper was missing its gasket, so it never actually sealed when the fireplace was cold. Third, the crown had a hairline crack and the cap was undersized, letting humid summer air and a little rain into the flue. Each finding explained part of the problem; together they explained all of it.
Why the smell kept coming back
Here is the chain. Humid summer air, pulled down the chimney by the air conditioner and a leaky damper, carried the smell of the creosote into the room — the exact mechanism we describe in the chimney symptoms guide. Previous sweeps had removed the soft creosote but left the glazed band, because a brush cannot cut glaze. So the odour source stayed in the flue, and the open damper gave it a path indoors every cooling season. Sweeping alone was always going to be a temporary fix.
The repair: three fixes, done once
The work was staged so nothing was done twice. A rotary cleaning system with flexible whips scoured away the stage-three glaze that the brush had never touched — the cleaning described on our chimney sweeping page. The failed top-sealing damper gasket was replaced so the flue finally sealed shut when cold, blocking the downdraft path. And the cracked crown was repaired and a correctly sized cap fitted to keep humid air and rain out, work covered on our caps, crowns and dampers page. A follow-up camera pass confirmed the flue was clean end to end.
The outcome
With the odour source gone and both entry paths sealed, the summer smell has no source and no route indoors. In an illustrative job like this the fireplace is usable again and the homeowner stops paying for a sweep that never held. The lesson is the one we repeat on every page: a symptom usually has more than one cause, and only an inspection tells you which ones are really in play. Guessing is what makes a problem come back.
What you can take from this
If a chimney problem keeps returning after it was supposedly fixed, the odds are good that the real cause was never found. Insist on a camera inspection before any repair, ask which creosote stage was present, and ask whether the damper and crown were checked — not just the flue swept. For what you can safely monitor yourself between visits, see our maintenance tips, and for the full set of guides, the chimney guides hub. We are bonded and insured, and every job starts with the same camera inspection shown here.
Case study questions
Is this a real customer story?
No. It is clearly an illustrative composite built from the kinds of jobs common around Bourbonnais, written to show our diagnostic process. It is not a named customer and it is not a review.
Why do you use an illustrative example instead of a real one?
To teach the process honestly without misrepresenting any individual or inventing a testimonial. The mechanics — camera inspection, finding multiple causes, staging the repair — are exactly how we work on real jobs.
Why did sweeping alone not fix the smell?
Because the odour came from glazed stage-three creosote that a brush cannot remove, and from a damper that let humid air pull the smell indoors. Removing only the soft creosote left both the source and the path in place.
What is stage-three creosote and why does it matter?
It is a hard, shiny glaze that forms when a flue runs cool or burns wet wood. It ignites most easily of the three stages and must be removed with a rotary tool, not a standard brush, which is why it is often missed.
How does a camera inspection change the outcome?
It replaces guesswork with evidence. Seeing the glaze band, the failed damper gasket and the cracked crown let us fix all three causes at once, rather than sweeping repeatedly and hoping the problem stayed away.
Could a problem really have more than one cause?
Very often, yes. Most chimney symptoms have two or three possible causes, and the lasting repair addresses the ones actually present. That is why we inspect before we recommend anything.
How would I know if my own chimney has this issue?
A campfire or asphalt smell from a cold fireplace, worse on humid days or when the air conditioner runs, is the classic sign. Our chimney symptoms guide walks through what each smell and stain usually means.
What should I ask a chimney company before a repair?
Ask for a camera inspection first, ask which creosote stage was found, and ask whether the damper, crown and cap were checked — not just whether the flue was swept. A good answer prevents a repeat visit.
Have a problem that keeps coming back?
Call for a camera inspection that finds the real cause the first time. Bonded and insured.
Call (815) 449-4264