Chimney maintenance you can safely do yourself — and what to leave alone

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Burn the right wood — this single habit prevents most problems

Creosote formation is driven mainly by two things: moisture content of the fuel and flue temperature. Wood at 20 percent moisture or less burns hot and clean. Green or unseasoned wood spends the first part of every fire boiling off water instead of producing heat, which cools the flue and condenses far more creosote onto the walls.

How to tell seasoned wood without a meter: it is noticeably lighter than green wood of the same size, shows radial cracks in the end grain, has bark that comes away easily, and makes a sharp hollow knock rather than a dull thud when two pieces are struck together. Split wood dries far faster than rounds, and most hardwood needs six to twelve months stacked off the ground with the top covered and the sides open.

A ground-level chimney check anyone can do

Twice a year, take a pair of binoculars and look at your chimney from the yard. You are looking for five things:

1. Mortar joints — recessed, cracked, crumbling, or missing sections.
2. Brick faces — flaking, pitting, or pieces that have popped off (spalling).
3. The crown — visible cracks across the concrete slab on top.
4. The cap — present, upright, mesh intact, no rust streaks running down the brick.
5. Lean or stair-step cracking — any deviation from vertical is worth a call straight away.

Inside, check the firebox for cracked firebrick and open mortar joints, and operate the damper to confirm it moves freely and seats fully. White chalky staining on exterior brick (efflorescence) means water is moving through the masonry and is worth reporting when you book.

Simple things that genuinely help

• Keep the damper closed when not in use — an open damper leaks conditioned air year round.
• Leave a one-inch ash bed in a wood-burning firebox; it insulates and helps coals establish. Clear anything deeper.
• Let ashes cool 48 hours minimum before disposal, then use a metal container with a lid, kept off any combustible surface. Ashes hold live embers far longer than people expect.
• Build fires toward the back of the firebox, not at the front, which improves draw and reduces spillage.
• Warm a cold flue before a full fire by holding a rolled newspaper torch up near the damper for a minute — this reverses a cold-air plug that causes smoke to roll into the room.
• Test smoke and carbon monoxide alarms at the start of every heating season.

Do not attempt these

We would rather lose the work than have someone hurt, so this list is blunt.

• Anything involving gas. Gas valves, thermocouples, pilot assemblies, and connections are not homeowner territory. If you smell gas, leave the building and call your utility from outside. See gas fireplace service.
• Roof work. Falls are the real hazard of this trade, far more than fire. Caps, crowns, and flashing all mean roof time.
• Chemical creosote removers as a substitute for sweeping. They may loosen light soot; they do not remove glazed deposits and are not a cleaning.
• Burning treated, painted, or construction lumber, or using accelerants. These produce corrosive and toxic combustion products.
• Sealing masonry with a film-forming waterproofer. It traps moisture inside the brick and accelerates spalling. Only vapour-permeable sealers belong on a chimney.
• Using the fireplace after a chimney fire until a Level 2 inspection confirms the liner survived. Chimney fires crack tiles invisibly from below.

When to stop and call

Call promptly for: smoke entering the room, a ceiling stain near the chimney, animal noise in the flue, a damper that will not move, visible spalling or a leaning stack, a strong odour that a sweep did not fix, or any gas smell at all. Our inspection page explains what we check and what a report includes.

If you are unsure whether something is urgent, phone and describe it. We will tell you honestly, and we do not charge for that conversation.

Fuel & heat output

Two fuel mistakes that make a good fire feel cold

Seasoning wood well keeps a flue clean, which is reason enough to get it right — but your fuel choices also decide how much of that heat actually reaches the room. If the fire looks healthy and the room still stays chilly, start with what you are putting on it.

Matching the fuel to the appliance and the species to the heat you want

Dense hardwoods such as oak, hickory, and sugar maple carry far more energy per load and settle into a long bed of coals that throws steady, lasting heat. Softwoods and lighter species flare up fast, look impressive, and are mostly gone in twenty minutes with little warmth left behind. Fuel also has to suit the unit: never burn solid wood in a firebox rated for gas logs, and do not feed pellets or coal into an open masonry fireplace that was never built for them. Construction offcuts, pallets, painted or treated lumber, and any accelerant stay off the list entirely — they burn dirty, attack the flue, and release harmful gases.

Why damp wood robs the room of heat

Freshly cut wood can be close to half water by weight, and every bit of that moisture has to be boiled off before the wood reaches a useful burning temperature. That energy comes straight out of your fire, so a damp load runs cool and smoky and sends lukewarm gases up a cooling flue instead of radiating heat into the room. Wood at or below twenty percent moisture lights easily, burns hot, and delivers the heat you are paying for. An inexpensive moisture meter pushed into a freshly split face takes the guesswork out, and it is the fastest way to turn a disappointing fire into a warm one.