Fireplace and chimney sweep

What does a chimney sweep remove?

Mostly creosote, which is what wood smoke turns into once it cools on the inside of a flue. It builds in three rough stages. First comes a dry, flaky soot that brushes right off. Left alone, it becomes a crunchy, tar-like crust that takes harder brushing. The third stage is a shiny glaze, almost like black enamel, and it’s the one to worry about, because it’s dense and it burns hot.

We brush the flue from the bottom with rods and a brush sized to the liner, with a vacuum pulling at the firebox the whole time. Then the smoke shelf, the ledge just above the damper, gets cleared of what falls on it: soot, chunks of creosote, and now and then leaves or a bird’s nest. The damper plate and frame get cleaned so the damper opens and seals properly. The firebox comes last.

Honest limitation: glazed third-stage creosote doesn’t come off with a brush. If we find it, we’ll tell you, and it’s a specialist’s job.

Gas fireplaces vs wood-burning

A wood fireplace makes creosote. A gas fireplace doesn’t, so the job is lighter, but it isn’t nothing. The glass front picks up a white haze from combustion. Ceramic logs and the burner tray collect dust, and the ports can clog. The vent, whether it goes up a chimney or out a side wall, still has to be clear.

We clean the glass, the logs and the burner area, and check that the vent isn’t blocked. What we don’t touch is the gas supply. The valve, the pilot assembly and the gas line are for a licensed gas technician.

In our opinion, a gas insert with a hazy glass front is the most overlooked fireplace in the house. People stop seeing the flame clearly and assume that’s just how it looks.

What speeds creosote up, and what slows it down

Burning dry, seasoned hardwood slows the buildup, because a hot fire sends less unburnt smoke into a cold flue. Wet wood, slow smoldering fires and a damper kept half shut speed it up, and they’re what push flaky soot into the tar stage and then into glaze. Two houses on the same street, burning the same number of nights, can have flues in completely different shape. So we look at yours, tell you what’s in it, and set the schedule with you.

A few signs mean don’t wait. Smoke coming into the room when the fire’s lit. A strong campfire smell in the house on a humid summer day. Black flakes on the hearth. The first one matters most: smoke that won’t go up the flue ends up in the air of the room you’re sitting in.

What we cover before we start

Everything near the opening. Drop cloths go down over the hearth and the floor in front of it, well past where anyone would expect soot to reach. The fireplace opening gets sealed around the vacuum hose, so the brush can work above it without anything drifting into the room. Rugs and furniture near the hearth get moved back or covered. It’s the same habit as the plastic we run over a kitchen’s cabinets before touching a range: if the room needs cleaning after we leave, we did the job wrong.

What needs a mason

A sweep cleans. It doesn’t rebuild, and the most useful thing we can do is be honest about the line.

• Liner: a cracked clay tile liner or a damaged metal liner is a relining job.
• Crown: the concrete cap on top of the masonry cracks with freeze and thaw, and water gets in behind the brick.
• Cap: a missing or rusted rain cap lets in water, leaves and animals.
• Brick and mortar: loose bricks, missing mortar and white staining on the outside.

We’ll point out what we can see, and you get it in plain words to pass along. We don’t do the repair, and we won’t suggest a sweep solves it.

We sweep a lot of fireplaces in village colonials and country estates in New Jersey and in river-town houses just north of the city. The same brush-and-vacuum approach goes into cleaning a dryer vent out to the exterior hood, and a wood-fired oven out back has the same soot problem on a smaller scale, which is why soot and creosote in a pizza oven dome gets its own page. Tell us how the fire has been drawing, and we’ll know most of what’s up there before the rods come out.