Chimney sweeping is the most important preventative maintenance a wood stove user performs. Burning wood inevitably creates ash and creosote that congeals on the inside of the chimney as the hot combustion rises through the flue, creating a clogging, highly flammable coating that must be removed periodically. Chimneys should be cleaned at least once a year, preferably more often, particularly if you burn resinous soft woods, like we do.
Chimney cleaning is a tough, unpleasant job. This is why so many house fires are chimney fires—it’s just too easy to procrastinate; this is a deadly mistake, but one, I hate to admit, that we make often.
We cleaned our chimney at the beginning of October, for what appears to be the first time in two years. We did okay, thanks, I’m sure to burning the driest wood we can find, and regular applications of Red Devil Creosote Destroyer. Besides the safety factor, we were amply rewarded for our efforts in less tangible ways.
Covering the wood stove and a good area around it with drop cloths will keep soot from covering your home as you work.
The chimney sweep’s primary tool is a chimney brush, found at most hardware stores and wood stove shops. This mass of wire bristles is a nasty piece of work—handle it with care to avoid puncturing your skin or clothing!
The brush has a metal loop at one end, and a threaded shaft at the other. The shaft accommodates fiberglass rods that can be joined together to make a handle long enough to reach up through a chimney from below. This is great if you have a fireplace flue to clean, but it’s useless if you have a wood stove, particularly the more modern kind with baffles to recombust smoke before sending it up the flue. These rods could be used from above, but I can’t imagine trying to balance myself and some 20 feet of pole at the same time. I use a rope and weight.
I attach about 30 feet of line to the loop of the brush—enough to reach the bottom of our two-story length of chimney, plus enough extra to allow for leverage and mistakes. I attach a weight to the brush, hanging it through the brush and securing it to the loop at the top with baling wire. For a weight, I use a quart yogurt cup with holes punched below the rim for the wire. I put 3 small pigs of lead in the cup. I’m on the look out for a metal can of about this size to replace the cup, as one sweeping session beats the crap out of it.
I climb to the roof peak and clip my safety harness to a line that runs from a tree in the front yard, up over the roof peak. As a rule, I go no farther across the roof peak on the line side than to straddle the peak with one leg. My goal, should I fall, is to do so on the opposite side of the peak from the line, so it’ll save me, rather than come plunking down on my dazed head after I’ve hit the ground . . . .
I wear a respirator mask and goggles to protect me from the toxic creosote. Heavy gloves keep my hands clean, and safe from the bristles.
In practice, sweeping involves removing the chimney cap and lowering the brush into the chimney, working it up and down in short, sharp strokes to scrub the insides of the pipe. The soot and creosote loosens and falls into the wood stove below, where it burns in the next fire.
However, the baffles that provide a more complete burn prevent large amounts of ash to fall into the stove. If too much accumulates in the baffles, they’ll clog.
In the past, we removed the base plate that joins the chimney to the wood stove, and additional sections of pipe as needed. We then wrapped the mouth of a garbage bag over the exposed pipe end. As we brushed the inside of the pipe, the ash and creosote accumulated in the bag with very little mess.
This year, we learned that the base plate screws had fused. We could not disassemble our chimney for cleaning.
Luckily, we have a branch chimney for our wood fired water heater. This joins the main chimney at a T-joint. Chimney cleaning includes removing the branch for brushing outside, so we can use the T-joint as an inspection port. We built a funnel out of cardboard to be inserted in the hole of the T. This caught the majority of soot coming down the chimney, preventing it from falling into the baffles.
I also left the yogurt cup, which holds my brush weights, open. This catches much of what I brushed off the chimney, to be pulled out and dumped. This accounted for almost all of the soot up to the bottom of the T-joint. We swept everything below it, about 4 feet of pipe, into the baffles.
Once we’d finished, we needed to find out if the draft had been clogged by the remaining soot. To do this, we lit a cone of incense and set it inside the wood stove. We watched through the open T-joint for smoke. If we didn’t see any, no matter, as the cabin fills with that much smoke anyway if we burn an incense cone.
We not only saw the smoke, but the area outside the cabin became fragrant with incense. We had not clogged the draw.
To complete the job, we cleaned the chimney cap with a wire brush, and reattached it.
About every third fire, we throw in a couple of tablespoons of Red Devil Creosote Destroyer. We know this stuff works well, as inspecting the chimney showed that very little creosote had accumulated. Most of what needed to be cleaned was soft, black ash. Regular applications through the burning season will make sure this big job is easy again next year.