What a chimney sweep actually removes

Creosote, soot, and whatever has fallen or crawled into the flue since the last visit.

Creosote is what wood smoke leaves behind when it condenses on the cool inside of a chimney. First season it is a light dust. Leave it and it hardens into a black glaze welded to the flue tile. That glaze is fuel. Enough of it in one spot, one spark on a cold night, and there is a fire burning inside the wall of your house.

Soot is the lighter deposit. It is also why a fireplace smells. Soot holds moisture, so the odor gets worse in humid weather and after rain. We get calls in July about fireplaces last lit in February.

The rest is debris. Twigs from nesting birds, leaves, chunks of failed mortar, and in older chimneys with a missing cap, the occasional dead animal. Los Angeles fireplaces get used a handful of nights a year, so a flue nobody runs is a good place for something to move in.

How often a chimney needs sweeping

Once a year for anyone who burns, and NFPA 211 calls for an annual inspection whether or not the chimney needs cleaning.

How you burn decides it. Weekend fires all winter put down enough creosote for an annual sweep. Three fires a year will not. The inspection still matters though. Deposits are only one way a chimney turns dangerous. Cracked flue tile. A cap rusted through. A damper that stopped sealing years ago. A nest sitting above the smoke chamber.

Signs it is overdue:

• Smoke comes back into the room when you light a fire
• The house smells of old fire, especially in warm weather
• Black flaking or a shiny tar-like coating visible in the firebox
• Fires are hard to start or burn lazily
• You bought the house and have no record of the last sweep

That last one comes up constantly. If you do not know when it was last done, assume it was not.

What it costs

Every price starts with a look up the flue. We quote before any work begins, and the quote is the price. If the technician gets up there and finds the job is bigger than the booking suggested, you get the number first. Nobody finds out on the invoice.

Many of our services carry a guarantee or warranty. Which one applies depends on the work, so ask when you book.

How a sweep runs

1. Drop cloths and containment

   Hearth and floor first. Then the path in from the door. Nothing gets touched until the room is covered.

2. Vacuum on before the brush moves

   A HEPA vacuum runs at the firebox for the entire job. The dust stays inside the fireplace.

3. Brushing the flue

   Rods and a brush sized to your flue, worked from the firebox or the roof depending on the chimney. One brush does not fit every chimney. Wrong size leaves deposits behind.

4. Smoke chamber and damper

   The shelf above the damper catches more debris than anywhere else in the chimney. It also gets skipped by anyone in a hurry. We clear it. Then we check the damper opens, closes, and actually seals.

5. Level I inspection

   Firebox, damper, smoke chamber and the accessible flue, checked while we are in there. If something needs attention you get told, with photos.

6. Deodorize where needed

   If the smell has soaked into the masonry, sweeping alone will not clear it. A treatment handles the rest.

7. Cloths up, room back to normal

   You should not be able to tell we were there, other than the fireplace working.

Sweeping is not the same as inspection

Sweeping cleans the flue. Inspection tells you whether the chimney is safe to use.

Every sweep includes a Level I inspection. No sense cleaning a chimney without looking at it. What it does not cover is the full length of the flue behind the tile.

For that you want a Level II, which sends a color camera the whole way up. You want one after an earthquake, before buying or selling a house, after any chimney fire, and any time the fireplace is being converted to gas. Escrow usually asks for it by name.

Read more about Level I and Level II inspections.