The plan was simple: drive up to the lake on Friday night. Snowmobile across the ice to the cabin. Fire up the woodstove. Get warm. Grab some shut-eye.
But when smoke spilled from a joint in the stovepipe, filling the cottage and setting off the carbon monoxide alarm, Courtney Bannatyne knew she and her boyfriend were in for a long night. As the temperature dropped to -35°C, with nowhere else to go, they huddled under blankets in their Northwestern Ontario cottage, prodding the feeble fire. “We were trying to keep the cottage from getting so cold that we’d freeze, but, at the same time, we were terrified of carbon monoxide poisoning from all the smoke.” In the morning, the culprit was easy to spot from up on the roof: the screen on the chimney cap was almost entirely plugged by hardened black creosote.
That comes as no surprise to Patrick Cormier, the owner of Master Chimney Sweep in Elgin, N.B. “The chimney cap is often the coldest part of the chimney and the biggest restriction on the flow of flue gases.” When tarry or sooty particles from a smoky fire hit the screen, they cool and form creosote. Too much, and the chimney is blocked.
Cottagers can cut down on creosote by burning seasoned wood in a hot fire. “Wood needs to be split and left to dry for about six months, enough time for it to get to 17-20 per cent moisture,” says Cormier, adding that when it’s time to kindle a blaze, you should leave the draft control open for 15-20 minutes to ensure that the wood “is completely charred,” before reducing the draft.
Check the chimney at least a couple of times a year by using a mirror to look up the clean-out or by shining a light down from the top. If there’s a layer of creosote thicker than two loonies (more than 3 mm) on the walls of the chimney, clean it out. And if you’ve got a screen on your chimney cap, Cormier recommends 1/2″ square mesh. “Anything smaller is just going to plug.”
It’s a little work. But on a cold Friday night, a trouble-free stove is its own reward.
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