Chimneys: Fire is not the ONLY risk!
Is your chimney in danger of causing a leaky roof that could result in a major roof repair or even a new roof?
Chimney leaks are problems we frequently encounter. These are easily preventable leaks that go can go unnoticed until it’s too late (can anyone say interior damage? or even worse, ROOF REPLACEMENT… ugh). Unfortunately,
an overwhelming majority of chimneys we see have not been shingled and flashed properly. The two biggest culprits are builders and roofing contractors that either (a) don’t have a clue what they’re doing, or (b) just don’t care enough to take the time to do it the right way. There are several things your roofer should do to ensure you never have a leak when your new roof is installed or your leaky roof is repaired.
Chimneys: What you should know to prevent a leaky roof
First, there are two different types of chimneys we deal with on a daily basis:
1 – Chimneys with siding, wood paneling, or cedar shake
2 – Chimneys with a hard surface like brick, stucco, or stone
There are some basic rules for both. Is your chimney on the side of your roof or does it fall somewhere in the middle? If it falls somewhere in the middle of your roof, (where water runs around the right and the left from the
back) you should have a cricket or a saddle.It looks like a little roof behind the chimney (see graphic to the right) that diverts water away from both sides of the chimney. When repairing or re-roofing around a chimney you should always make sure the decking around the area is not rotted. Rotton decking prevents shingles from being fastened properly during installation. If a shingle is loose there is a greater chance that that area will leak again. Rotted decking that is not replaced can also spread if not replaced and shingled over. If your chimney has siding, make sure the siding and corner posts are taken off. Ice & water shield should be installed on the deck and onto the sheathing behind the siding (make sure it covers the cricket as well). The ice & water shield should be wrapped from the bottom up to prevent water from
getting inside where the ice & water shield overlaps. The four areas of the chimney should have step flashing woven in between the shingles (this includes both sides of the cricket on the back of the chimney as well as the left and right sides of the chimney). There should be a piece of step flashing sticking out beyond the corner posts to help divert water away from the chimney (this is called a kick out). On the bottom side of the chimney there should be a piece of L flashing. The L flashing should be nailed to the chimney sheathing and should be on top of the shingles. You want it on top so that water does not travel below any of the shingles. Finally, all of your siding and corner posts should be reinstalled and caulked.
If you have a hard surface chimney, the install is very similar, but with a few exceptions. When the house is built the flashing will be installed prior to the brick, stucco or other hard surface being installed. So the metal is behind it. Obviously you can’t remove the metal at this point. When you have repaired the decking, and the ice and water shield has been installed, the shingle step flashing is woven in between the shingles on both sides of the cricket and on both sides of the chimney. The L flashing is installed the same way on the bottom. Then all exposed metal should be capped with counter flashing fastened with concrete nails. The top of the counter flashing has a channel should be filled with a special roofing caulk.
Another common source of chimney leaks are chimney pans. A chimney pan is the piece of metal that sits on top of the chimney directly below the exhaust. The pan should completely cover the opening on top as well as the sides. The pan should drop down 4-6″ on the sides of the chimney and have enough roof to comfortably fit. It should be attached with screws not nails. The top of the pan should not be flat. It should angle away to all for corners from the hole where the flute comes through so water sheds properly. The hole should also have a lip to prevent water from getting inside the chimney. The flute should also have a rain collar and a cap. Finally, it should also have a painted finish to prevent rusting.
If inspect your roof and believe you are facing any of these issues, are uncomfortable with what you see, or if you just don’t know, fill out the form on our home page or call us at (770) 400-0998. We will provide you with a custom solution that fits your needs. We also provide maintenance programs to prevent these issues from occurring in the future and to maximize the life of your roof. And, if it IS time for a new roof, we offer free estimates. Just complete the form on our home page and we will contact you very soon. We are also your Custom Metal Roof expert.
Finally, if you enjoyed this article, check out our other articles in the Knowledge Center. We have lots of great roofing information to help you better care for your home. Also, please don’t forget to share this article with your friends. Convenient buttons appear just below this post.
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