A green meadow beside a pond, with bare cottonwoods and willows behind it under a clear, pale blue sky

Chimney sweeping and cleaning in Thornton.

A sweep takes the soot coating off the walls of the flue and the smoke shelf, and clears the firebox and any stove pipe. Call, or use the form when it is convenient.

An illustration of the smoke chamber above a fireplace opening, where creosote settles
Illustration

Photo: Stock pond near Barr Lake (146443605), Louis, CC BY-SA 2.0

Sweeping, one stage at a time.

What leaves the flue, how often it should, and what to settle before the first fire of the season.

  1. What comes out of the flue.

    Each fire leaves a thin film on the flue walls. Fresh soot is dry and brushes away. After many slow, cool burns it turns into sticky tar, and finally into a hard, glassy glaze that even a stiff brush barely moves.

    We start at the damper and brush toward the cap, then deal with the smoke shelf, and last the floor of the firebox. Everything loosened is collected and carried off, so nothing stays behind to burn later.

    A soot-stained brick firebox with an orange cable running down its middle and a ribbed black vacuum hose at the right, under a dark steel lintel
    From our Google Business Profile
  2. How often should it be swept?

    How you burn sets the pace. A fire every evening lays down a coating far faster than a few fires a winter, and a thick or shiny coating means the next sweep should not wait.

    NFPA 211 advises a yearly look at the chimney. That look gauges how much deposit there is, so sweeps and inspections are frequently done on one visit.

    For scale: the Census Bureau (American Community Survey, 2020 to 2024) counts 35,207 of Thornton's 50,566 occupied homes as heated mainly by utility gas and 13 by wood, with a margin of error of 21 on the wood figure. A fireplace used seldom still builds up some deposit, which is why the annual look takes priority.

  3. The payoff of a clean flue.

    Chimney fires start when creosote that has piled up catches light inside the flue. With the deposit gone, a stray spark has nothing to cling to.

    Draft improves too: smoke goes up and out, where a coated flue lets it spill back as soon as the damper opens.

    An illustration of a chimney cut open to show the flue running up through it
    Illustration
  4. Wood stoves and inserts.

    Turning a stove down for the night keeps its fire cool, and cool smoke lays down creosote fastest, above all in the connector pipe that links stove to chimney.

    A stove visit follows the whole path: first the connector and its joints, next the flue or liner, last the cap.

  5. At the very top.

    By the time smoke reaches the cap it has cooled, and cool smoke leaves soot behind. Clogged mesh weakens the draft, but that same mesh holds embers in. We clean it each time.

    An orange-brown brick chimney with a flat grey concrete top and a steel cap with black mesh, in front of a grey hip roof and a tan and brown wall
    From our Google Business Profile
  6. Smells in humid weather.

    The smell is creosote. A flue that has seen use keeps a trace of it, and thick damp air, or a draft running the wrong way, brings it down into the house. Sweeping removes the source; a shut damper and a cap hold in what is left.

Ask for a sweep

Questions about sweeping.

Short answers, with a source named where one exists.

When is a sweep due?

Go by how much deposit there is, not by the date. NFPA 211 advises a yearly inspection, which shows the amount and the kind. A shiny or tar-like coating should be dealt with soon.

Sweep, inspection or both?

Sweeping removes deposits. An inspection judges the whole chimney, from top to bottom, at one of three NFPA 211 levels. Because soot can hide damage, one visit often does both.

What does glazed creosote mean?

It is creosote cooked into a hard, glossy, tar-like skin, typical where smoke cools slowly, for example in a stove damped down overnight. A brush hardly shifts it, so finding it means you should book soon.

Does a gas fireplace need sweeping?

Burning gas produces no creosote, but the vent has to stay open. Nests, leaves and flakes from a worn liner can block it, so have the vent checked from time to time.

Why does it smell worse in summer?

Warm, damp air brings out the creosote smell, and a downdraft can carry it indoors. Take the deposit out and the cause is gone.

How do I schedule a sweep?

Call (720) 964-2146 (Sunday to Saturday, 7 AM until 9 PM). The form further down is open at any hour, and a person calls back to fix a day.

Set up your chimney visit.

Use the form to say what looks wrong, or simply phone. A person rings you back to pick a day.

  1. 1Reach out Call the office, or send a few lines on the form.
  2. 2A person rings back Someone phones to find a day that suits you.
  3. 3Cap to firebox The visit works down the chimney in order, the roofline first and the hearth last.
  4. 4Your call We say what we found, and you decide what comes next.

By phone

Sunday to Saturday, 7 AM until 9 PM

(720) 964-2146

By form

Any hour, day or night

Photo: Hail Storm Park And Streets I, Eric Johnson, CC BY-SA 3.0

What do you need?

What do you need?

About your chimney

What do you burn?

How do we reach you?

Best time to call

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Planning a fire before the first hard freeze, or puzzled by something up on the roof? Ask us.

Our phone line is staffed Sunday to Saturday, 7 AM until 9 PM, and the form never closes.

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