The laboratory book
The ridge, graded
What we do
The three degrees, and what each one gets
First degree — the brush
Flaky, soot-heavy, a season of seasoned cordwood laid down thin. It brushes out behind a sealed hearth on HEPA extraction in under an hour, and the card reads “first degree, all runs” — the grade every household hopes for and about half of them earn. Burn dry wood and this is the only degree you ever meet.
Second degree — the rotary head
Creosote that has hardened into shiny plates, usually from damp flue gas cooling too fast in an outside chimney. The rotary head strips it the way a plane strips paint, the plates fall into the HEPA stream, and the follow-up camera pass proves the wall behind them is sound. Ignored, second degree is next year’s third.
Third degree — the chemistry
Glazed tar, dense as toffee, the fuel chimney fires actually run on. Brushing glaze only polishes it, so it gets a chemical modifier that breaks the glaze down over days, then a second visit with the rotary head and a camera pass that must show bare wall before the card gets signed. It is the one degree we never hurry.
The camera
A rod-mounted head down every foot of flue, recorded. Degrees are graded from your walls, not from the calendar, and the footage is yours to keep.
The HEPA rig
Sealed hearth, negative pressure at the throat, every gram of what comes down captured. The room is cleaner after a Cindermark sweep than before the van opened.
The manometer
Draft read in pascals before and after, on the card. A flue that sweeps clean but still will not draw is a diagnosis, not a mystery — and the reading says which.
The previous sweep “cleaned” this flue twice and it still smelled like a tar barrel by August. Cindermark’s camera showed third-degree glaze from the smoke shelf up — fuel, waiting for a cold snap and a hot load of pine. Two visits, chemical treatment between, and the follow-up footage showed bare clay for the first time in years. They graded the old cards wrong, and the video proved it frame by frame.
Dovetail Ridge, 2025 — 2026
Graded and treated
Six flues from the laboratory book, photographed at the follow-up camera pass. The grade on the card is the grade on the wall.
They found second degree the last outfit photographed and never mentioned. The before-and-after footage is the sales pitch I never needed — plates on the wall, then bare clay, same chimney, ten days apart.
Our stove smoked the room whenever the wind came off the ridge. The manometer reading told them the flue was oversized for the appliance — a smaller rigid liner, and the smoke problem ended the day it was lit. No amount of sweeping was ever going to fix geometry.
Third degree on the card frightened us into doing everything right, which is the point of an honest grade. Two visits, a chemical that smelled of nothing much, and a follow-up video that ended the argument. They charge for the second visit and say so up front — the only surprise on the invoice.
The laboratory five
Degrees, answered
The questions every ridge household asks by the second minute of the first call. If yours is missing, the lab line runs seven to five.
How do I know which degree my flue has?
You do not, and neither does anyone quoting over the phone — the grade lives on the flue walls. The camera pass grades it foot by foot on the first visit, and the card names it. Anything else is a calendar guess wearing a uniform.
Can second degree become third?
Reliably, given a damp flue and a season of cool smouldering fires. Second-degree plates cook into glaze the way syrup cooks into toffee. The rotary pass strips the plates while they are still plates — which is why we treat the degree, not the date.
Is the chemical treatment safe for a wood stove?
The modifier is applied to the glaze itself, breaks it into brushable soot over several days of normal use, and burns off leaving nothing in the flue. The stove stays in service through the treatment; only the second visit’s card depends on it.
Why does my flue creosote faster than my neighbour’s?
Outside-wall chimneys cool the flue gas faster, big liners slow the gas below the condensation point, and damp or soft wood doubles the tar in the stream. The card’s readings tell you which of the three is doing it — one is a burning habit, one is a liner size, one is geometry.
What does the grade have to do with chimney fires?
Everything. A fire needs fuel, and third-degree glaze is the only form dense enough to sustain one. A flue graded clean to bare wall has nothing to burn — which is why the follow-up camera pass, not the sweep alone, is what closes a third-degree card.
Grading visits inside the week, ridge-wide · (555) 045-9821 · lab@cindermarksweeps.example
Get your grade
Tell us what you burn, how often, and whether the room smells by late summer — the pattern predicts the degree surprisingly well, but the camera settles it. Sweep and graded card from $189; the footage is yours whatever it shows. lab@cindermarksweeps.example