How To Fix A Leaking Chimney?
July 19, 2023
Types Of Leaks And How To Fix Them
Damaged or Poorly Installed Chimney Chase Cover
If you have a wood framed chimney with a prefabricated fireplace and are experiencing a leak coming from around your chimney, it is likely caused by a damaged or poorly installed chimney chase cover. Many times roofers go to homes to fix a leak that is believed to be caused by the roof flashing but it is actually caused by the chimney chase cover. Wood framed chimney chases are often quickly pieced together with inferior steel to get the job done as economically as possible. Over time, the inferior steel will rust due to the cover sagging in the center which allows water to pool on the cover.
The covers will eventually rust through, causing a leak. If your chimney cover is not rusting and you are still getting a leak, it is likely caused by the nails or screws going through the top of the chase cover to attach the cover to the chimney. The fasteners going through the top of the chimney will cause water to pool at the top of the chimney making the leak worse. If you have a wood framed chimney chase, you should inspect it immediately and replace it if it shows any signs of rust, or water pooling.
The Fix: Install a Stainless Steel Chimney Chase Cover
Replacing a rusty and leaking chimney chase cover is a very simple job that any DIY homeowner can do. A stainless steel chimney cover is superiorly constructed, it will not rust and will be a lifetime solution for your chimney. The stainless steel cover will have cross breaks on the top of the cover which elevates the center of the cover and allows for water runoff. If you live near the ocean and get a salt spray, you will want to use a 316L grade of stainless steel. Otherwise, 304L stainless steel is the industry standard for stainless steel chimney covers. The stainless steel covers are custom fabricated to fit your specific chimney.
Chimney Flue is Not Covered
If you look up at your chimney and you do not see a chimney cap, your chimney may be about to start a terrible leak. Over time the constant rain water flowing down the chimney will wash away the mortar joints between the flues and work its way down to your home. There is essentially a giant hole at the top of the chimney letting rain and snow go down the flue. This can cause stains around the perimeter of the chimney, requiring you to do some ceiling patching and painting.
The Fix: Install a Chimney Cap
Installing a chimney cap will prevent excess rain and snow from entering the chimney. A bolt on a single flue chimney cap is an economical option for a simple flue cap. There are also larger and more decorative chimney caps such as the outside mount multi flue chimney cap with the hip and ridge lid. This type of cap is going to have superior rain protection while also adding a decorative accent to the top of the chimney. The outside mount cap is also going to extend the longevity of the cement crown at the top of the chimney.
Cracked or Broken Crowns
A cracked or broken crown is one of the easiest parts of the chimney top to overlook, especially if you never go on your roof. The crown is generally out of sight, out of mind until there is a problem. Even if the chimney crown is fairly new, the wrong type of mortar being used or not allowing the crown to cure properly can cause cracks. If the cracks become large enough, the water will work its way to the lowest point and cause stains around the chimney requiring some wall patching and painting. Inspecting the chimney crown should be done annually to avoid the chimney crown from getting too bad.
Fix 1: Install A Stainless Steel Chimney Chase Cover
The best solution for fixing a damaged chimney crown is to cover it completely with a stainless steel chimney chase cover. The chase cover protects the crown so you will never have to worry about repairing the crown again. The stainless steel chimney chase cover will not rust or need to be replaced. The only maintenance that may be required is the seal between the flue and the collar of the chase cover. If you use a good UV protectant silicone, you will not have to worry about that for a very long time.
Fix 2: Seal The Crown
A good way to fix a chimney crack is to patch the cracks with mortar and then apply crown coat brushable sealant to the chimney crown. This is a silicate based pliable compound that will coat the chimney very well. The crown coat will expand and contract with the heat cycles and prevent any cracking for a long time. You will need to apply the crown coat every 10 to 15 years.
No Chimney Cricket At The Roofline
If your chimney is on the eve side of your home, a chimney cricket is essential to preventing a leak where the chimney meets the roof. A chimney cricket is a wedge that is the width of the chimney that diverts the rain water around the sides of the chimney. A chimney without a chimney cricket will allow all the rain water to come down the room and pool behind the chimney. Even if the roof flashing is good around the chimney, the lack of a chimney cricket can still cause a leak.
The Fix: Install a Custom Stainless Steel Chimney Cricket
Well built homes construct the chimney cricket as part of the roofline with the proper roof valleys and ridge shingles. Constructing a chimney cricket in that manner on a home without one can be a big undertaking. The best solution would be to have a custom stainless steel chimney cricket. All you need to do is measure the width of the chimney and the pitch of the roof to get one constructed. You simply cut away the shingles in the profile of the cricket and tuck the flashing underneath the shingles and seal it. If you notice your chimney is on the eve side of the home without a cricket, you should install one immediately.
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