Why Your Chimney Leaks: Common Causes of Chimney Problems
This article is brought to you by Washington DC area fireplace and chimney specialists High’s Chimney Services.
As we approach the colder months, many of us surely want to know that all is right with our fireplaces and chimney systems. Sometimes there are problems that must be addressed prior to enjoying a winter of cozy fires. One major issue is chimney leaks. Your chimney could potentially cause further problems, so it is important to deal with the smaller glitches early on. Let’s look at some reasons why your chimney leaks.
1. The fireplace flashing is cracked or torn.
The flashing is the material, usually aluminum, which surrounds the part of the chimney that pokes out of your rooftop, and bends over both the side of the chimney and roofing shingles. Flashing keeps water from coming down between the chimney and roof. Waterproof tar usually seals the flashing to prevent flashing leaks, but this eventually wear away, causing problems later. Specialty sealing products (such as FlashSeal) last longer than tar and does the job right.
2. Cracks develop in mortar joints and bricks.
Over time, the mortar and cement holding the chimney together may crack, and so do the bricks themselves. When this happens, water can fall down inside of the chimney and the house. Worse still, chimney walls in shaded areas will stay wet longer after rain and the bricks will also absorb this water and eventually expel it into the house.
One way to determine if this is the problem is by performing a Masonry Absorption Test (MAT). The MAT involves placing a test tube on the side of the chimney and gauging how long it takes for water to be absorbed into the chimney wall. Depending on the results of this test, you may find out that your chimney must be waterproofed. This can be done with specialty brick sealants (such as ChimneySaver) that will guard against water from leaking in without trapping the water inside the bricks and ruining them.
3. Loose knots and cracks in wood siding.
Two possible scenarios can affect the health of your chimney when your house has wood siding. In one case, knots in the wood will either come loose or come off altogether. In the other, the wood may get old, dry out and split. In both cases, water can get behind the siding and leak into the chimney and the house. The best course of action here is to just have a professional come out and check to ensure that everything in both the siding and chimney is sealed properly.
4. There is no chimney cover.
When your chimney has no cover, rain and other undesirable things (leaves, bugs and even birds) can fall straight down inside it. The easy fix here is to just invest in a chimney cover. Without one, not only will water leak in, but the other gunk will too, which is worse because it can clog the chimney and cause smoke to back up into the house. No one wants drafting problems or CO poisoning.
5. The chimney crown is cracked.
The chimney crown is the cement surface at the top of the chimney, which functions to keep rain out. When it becomes cracked, water can seep in and cause problems. Worse is the case of prolonged damage, as a crack left untreated over time will absorb water, which freezes in cold weather. Repeated freezing causes the crack to expand and becomes harder to fix. Cracks in the crown can develop for any number of reasons, one of which includes shifts in the entire chimney structure. Luckily, if the problem is caught soon enough, specialty coatings (like Crown Coat) can seal up small cracks and protect the crown from further damage. Larger cracks will unfortunately necessitate replacing the crown altogether.
A chimney leak can occur for any number of reasons and is usually fixable. It is important to detect issues early and take action to avoid serious problems (and large expenditures). Take care to inspect your fireplace and chimney each year and you will be in shape to face the harsh winters!
Northeastern Chimney, Inc.
formerly Nayaug Chimney Services, LLC
37 Cody Street, West Hartford, CT 06110