Chimney Maintenance Guide: What You Can Do Yourself, Step by Step
Eight checks that need no ladder and no special tools, plus an honest list of the work that belongs to a professional.
By Mark Jason, owner of NWI Chimney Sweep · written from 34 burning seasons of service calls
Tools you need:
- A firewood moisture meter
- A bright flashlight
- Binoculars
- A metal ash bucket with a tight lid and a metal scoop
- Work gloves, a dust mask and safety glasses
What a professional visit costs is listed on our chimney service pricing page; nothing on this page requires buying a service.
Should you do this yourself? Four quick checks
Routine chimney care is a do-it-yourself job only if the flue was inspected within the last 12 months and shows no thick or shiny deposit. These four checks decide whether to carry on or call a sweep first.
| Check | Fine to carry on | Stop and call |
|---|---|---|
| Has the chimney been inspected in the last 12 months? | Yes, with a written report | No, or you just bought the house |
| Scratch the flue wall above the damper with a poker. What comes off? | Thin, dusty soot | A layer 1/8 inch thick or more, or anything shiny and hard |
| Is anything visibly wrong from the yard? | Cap in place, bricks tight | Missing cap, leaning stack, loose bricks |
| Is the appliance wood or gas? | Wood fireplace or stove | Gas: limit yourself to steps 5 to 8 |
Where those thresholds come from
The 1/8-inch figure is a rule of thumb widely used in the chimney trade for when a masonry fireplace flue is due for sweeping, and any glaze means sooner. NFPA 211, the standard we work to, calls for a yearly inspection regardless of how much you burn.
The eight chimney maintenance steps
The eight steps below run from the woodpile to the alarms, ordered so the habits that prevent the most creosote come first.
Test your firewood before you stack it indoors
Split a log and press the moisture meter pins into the fresh face, not the weathered end. The EPA’s Burn Wise program puts the target at less than 20 percent and says to season wood for at least six months. Oak cut in a humid NWI summer often needs a full year. Wet wood burns cool, and a cool flue is where creosote condenses.
Build smaller, hotter fires
Open the damper fully, set kindling on top of two or three splits and light from the top so the flue warms quickly. A smouldering fire with the air choked down makes more deposit in an evening than a brisk fire makes in a week. Never burn painted or treated lumber, cardboard or trash.
Empty ash the safe way
Leave about an inch of ash as a bed for the next fire and shovel the rest into a metal can with a lid. Buried coals can stay live for days, so the can goes outside on concrete or bare ground, away from the deck, the garage and the siding. Never use a paper bag, a plastic pail or a shop vacuum.
Look up the flue with a flashlight
With the firebox cold, open the damper and shine a light upward. Dull black or brown dust is normal. Crunchy flakes mean it is time for a sweep. A glossy, tar-like coating is stage 3 creosote: stop burning and do not try to brush it. While you are there, look on the firebox floor for thin curved pieces of clay tile.
Work the damper through its full travel
A throat damper should open and close without grinding and sit flat when shut. Rust flakes on the plate mean water is coming down the flue. If it is stuck, warped or will not seal, note it; freeing a seized plate usually means working from inside the smoke chamber.
Check the top from the ground with binoculars
Stand back in the yard and find the cap: it should be present, level and its mesh intact. Then look at the crown (the concrete or mortar slab at the top) for cracks, at the mortar joints for gaps, and at the brick faces for flaking. Step to each side of the house so you see all four faces and the flashing line where the chimney meets the shingles.
Read the stains
White, powdery streaks on the brick are efflorescence, salts carried out by water moving through the masonry. Brown streaks under the cap point to rust or creosote wash. Inside, a water ring on the ceiling beside the chimney usually traces to flashing. Photograph anything new so you can compare next season.
Test smoke and carbon monoxide alarms
Press the test button on every unit monthly. The Consumer Product Safety Commission advises a CO alarm on every level of the home and outside each sleeping area. Any home with a fireplace, gas logs, a furnace or a gas water heater needs them, because every one of those appliances relies on a flue to carry exhaust out.
Stop here and call a professional if you find any of these
Stop and call a qualified sweep if you find glazed creosote, broken flue tile, animals, or anything that needs a roof or a gas fitting.
- Glazed creosote. Hard, shiny deposit does not brush off; it needs chemical treatment and rotary tools, and scraping at it can crack the tile underneath.
- Tile shards or mortar chunks in the firebox. The liner is failing and heat can now reach the brick and framing around it.
- Nesting material, droppings or scratching sounds. Chimney swifts are federally protected while nesting; removal has to wait or be handled correctly.
- Anything requiring a roof. A wet or frosted roof pitch is where homeowners get hurt. Caps, crowns and flashing are ladder-and-harness work.
- Any gas component. Valves, pilot assemblies, thermocouples and gas lines should be serviced by a qualified technician, not adjusted by trial and error.
What a sweep does that this routine cannot
A professional sweep removes the deposit already on the flue walls and inspects the liner’s full height, which homeowner care cannot do. Your eight steps slow the build-up and catch problems early. They do not remove what is already on the flue walls or see past the first few feet. A professional chimney sweep and cleaning visit runs a brush matched to the flue’s size and shape through its whole height, cleans the smoke chamber and shelf where most deposit hides, and contains the dust with a HEPA vacuum. A chimney inspection with a camera scan looks at every tile joint from the inside. If the binoculars turned up a problem at the top, our pages on chimney caps, crowns and dampers and masonry chimney repair describe the fix, and gas owners should read about annual gas fireplace tune-ups. Not sure what a symptom means? The chimney symptom checker sorts them out.
Chimney maintenance questions
How do I know if my firewood is dry enough to burn?
Use a moisture meter on a freshly split face; a reading under 20 percent is the EPA Burn Wise target. Without a meter, seasoned wood is lighter, has cracks radiating across the end grain and makes a sharp clack when two pieces are knocked together instead of a dull thud.
How long do fireplace ashes stay hot?
Longer than most people expect. Coals insulated under ash can hold enough heat to start a fire for several days, which is why they belong in a lidded metal container stored outdoors on a non-combustible surface and never in the garage or on a wooden deck.
Can I clean my own chimney with a brush kit from the hardware store?
On a straight, short flue with only dusty stage 1 soot, a correctly sized brush will move most of it. The limits are real, though: a brush that is the wrong size or shape skips the corners, the smoke chamber is hard to reach, and you cannot see liner damage. Treat it as a supplement to a yearly professional inspection, not a replacement.
Do creosote sweeping logs work?
They contain a catalyst that can dry out some deposits and make them more brittle, so the next brushing is easier. They do not remove creosote from the flue, and they do nothing for a blockage, a cracked tile or a missing cap. Use one if you like, but it is not a sweep.
Should I close the damper when the fireplace is not in use?
Yes, once the fire is completely out and the ashes are cold. An open throat damper is an open window for heated air. Never close it over warm coals, because a smouldering fire produces carbon monoxide with nowhere to go.
What should I burn in a fireplace, and what should I never burn?
Burn dry, split hardwood or manufactured fire logs used as their label directs. Do not burn painted, stained or pressure-treated wood, plywood, particle board, glossy paper, cardboard or household trash; they release corrosive and toxic compounds and can overfire the flue.
When is the best time of year to do chimney maintenance in Northwest Indiana?
Late summer into early fall. The masonry is dry, any repair mortar has time to cure before the first hard freeze, and you are ahead of the rush that starts with the first cold snap off the lake. Doing your chimney maintenance in September also leaves time to fix whatever the checks turn up.
Is it safe to go on the roof to look at my own chimney cap?
We advise against it. Binoculars from the yard show a missing cap, a cracked crown or open mortar joints well enough to know whether something needs attention, without the fall risk. A frosted or dew-wet shingle gives no warning before it lets go, and no view of a chimney cap is worth that.
Prefer to have the flue swept and inspected for you?
Call and ask for a sweep with a Level 1 inspection. Phones are answered 7am to 9pm, seven days a week.
Call (219) 203-9797