Most people never give their chimneys a thought — except in December when Santa's on his way. Maybe if they have a wood-burning fireplace, they know to get their chimney cleaned; maybe not.
But every chimney needs regular maintenance.
Think about it: Your chimney sticks up above your roof into the elements. It's exposed to all kind of weather — rain, snow, freezing and thawing. It's going to need attention just like every part of your home. And if you neglect it, it can lead to a world of trouble. Bricks from your chimney can fall down and injure people or break holes in your roof. Water can leak into your attic or living space, and gases leaking through a corroded chimney liner can deposit residue and soot, or even kill you.
Visual inspection
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From the ground, take a good look at your chimney. Do you see any crumbling, loose or missing mortar? Are any bricks or stones loose? Do any stick out unevenly? Does your chimney lean? (I sure hope not...)
If there is damage or wear you can see on the outside of the chimney, you can bet the inside is even worse. And, not trying to scare you, there might also be deterioration that you can't see from the exterior of the chimney that could make it unsafe.
At some point, every chimney's mortar needs repair, especially on the windward side — the side that gets the most weather exposure in your area. The job involves chipping out the loose mortar and refilling the spaces between the bricks with new mortar. It's called repointing (or tuck pointing) and it's not as simple as it looks. You need a professional to do it right. If your chimney is in really bad shape, it may need to be taken down and completely rebuilt. That's a huge job, and one you can avoid if you maintain your chimney properly.
If you don't have a wood-burning fireplace, you probably only use the chimney for venting the furnace, hot water heater or other appliances. If you've changed to a direct-vent furnace and appliances — they vent directly out through the foundation or walls of the house — you may not need a chimney any longer. That might save you the expense of rebuilding it. But you'll still have to have it taken down and properly capped if it's unsafe.
Water is the enemy
A typical masonry chimney is built from bricks and mortar with a metal or terra cotta liner, and every part if it will deteriorate through contact with water. Brick is very porous and it will absorb a lot of water, then wick it to the chimney interior.
The freeze/thaw cycle is very destructive: Water penetrates the mortar and brick, then, when the water freezes, it expands and helps crack the mortar and pulverize brick until your chimney is no longer safe. Water damage to masonry chimneys takes years and might not even be evident until it's already a serious problem.
Sometimes people will use paint on their chimney, thinking it will waterproof and protect the bricks and mortar. That's a bad idea. If the paint isn't vapour-permeable and seals the brick, it will trap moisture inside the chimney. That will speed up the deterioration process.
There are new products that have been developed for waterproofing chimneys. These are vapour permeable — they let the chimney breathe out, but not in. If moisture penetrates the chimney brick, it can escape, but water is prevented from entering from the outside.
Safety check
If you've just moved into a house that's been renovated, make sure you have the chimney checked. Contractors doing renovations without permits will sometimes use the chimney as a chase — a route for wiring, plumbing or even gas lines — between floors. It is dangerous — and illegal. That's not what a chimney is for.
Also, I've seen people — usually in a bad reno or a flip — hook up the vent from a gas stove with the chimney cavity, when it's supposed to be directly vented to the outside. They must have hoped the fumes and carbon monoxide would go up the chimney. Guess what: It doesn't, and it can kill you.
Chimney fires
Wood-burning fires deposit creosote on the inside of your chimney. Creosote is highly flammable and creates a serious fire hazard if you don't clean your chimney regularly.
Chimney fires can reach over 1,000 degrees Celsius — easily hot enough to destroy the chimney liner and very likely burn down your house. Have your chimney professionally cleaned every year.
Regular inspections
Many people with gas furnaces but no fireplace think that, since gas burns pretty cleanly, they don't have to worry about their chimney. But animals love to build nests in chimneys and that can block the flue, which will cause improper venting and possibly lead to dangerous fumes being forced back inside your home.
You should only have inspections and repairs done by a professional, and make sure they have insurance for themselves and your house. If they fall off the ladder, you are liable if they are uninsured. And if the chimney falls through your roof or your neighbour's, who's going to pay for it?
Mike Holmes is the host of Holmes on Homes on HGTV. E-mail Mike at mikeholmes@holmesonhomes.com or go to www.holmesonhomes.com.
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