What’s Wrong With This Picture?
A. The chimney is twisted and needs to be replaced.
B. You can’t install a chimney like that.
C. The chimney is leaking and needs to be replaced.
D. You can only install metal chimneys.
The correct answer: C. The twisted chimney is called corbeling and can be done as long as the bricks are not too far offset. What actually is wrong is the chimney has settled and, as a result, the flashing has pulled loose and is causing the chimney to leak. The chimney does not need to be torn down, but it’s definitely time for some maintenance.
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Your Chimney Liner
Most chimneys are constructed with an inner lining system made of clay tiles. The purpose of this liner is to keep heat and gasses inside the chimney so the chimney doesn’t overheat and ignite nearby combustible materials, such as the frame of the house. The liner also keeps the products of burning — such as carbon monoxide, moisture, smoke and creosote — from seeping into your house.
Not all chimneys were built with liners. For example, masonry chimneys built before 1940 weren’t built with liners, so it’s important for a home inspector to check that a liner was added to those chimneys. And, even if a chimney has a liner, that doesn’t mean the liner is in good condition. Clay tiles can crack, chip and break. If that’s the case with your chimney liner, you should have it replaced, as carbon monoxide and other contaminants can seep into your home.
Don’t rely on a home inspector to tell if a chimney liner is in acceptable condition. A home inspector can check the liner as far as he can see — usually a few feet — but to really tell the condition of a chimney liner, you need to call a professional chimney sweep service. Some chimney professionals use a video camera to scope the depth of the chimney to inspect the liner. In Canada, be sure your chimney sweep professional is certified by Wood Energy Technology Transfer, Inc. (WETT).
One thing that can damage a chimney liner is a chimney fire — often caused by a dirty chimney. A chimney fire can cause the tiles of a chimney liner to overheat and crack. So, if you’ve had a chimney fire, don’t use the fireplace until you have the chimney and liner inspected by a professional chimney sweep service.
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