Bill Ragan | Roofing materials, Chimney Leaks
There are a lot of areas on your roof that are prone to leaks. To combat this, roofing contractors have materials and techniques to keep water out of your home.
One of these potential leak areas is around your chimney. That begs the question, what goes around a chimney to prevent it from leaking?
We here at Bill Ragan Roofing take pride in helping you and other homeowners understand their roof, even the chimney. That’s why we’re going to cover the roofing material contractors use to prevent water from getting into your home through the chimney.
Here, you’ll learn the material that’s placed around a chimney, the different types, and more.
Roof flashing is placed around a chimney to prevent leaks
To prevent chimney leaks, a piece(s) of metal material is installed where the chimney comes through the roof. This metal material is called roof flashing.
Roof flashing directs water away from certain areas of your roof, including the chimney. As water flows down your roof, it ensures the space where the chimney comes through the roof is sealed and watertight.
Even though your chimney has flashing around it, there’s still the potential for a leak to show up. There are two main reasons your chimney leaks due to problems with the flashing.
The first reason is that the roof flashing was improperly installed. When this happens, your chimney has nothing stopping the water from getting inside it and getting into your home.
For this chimney leak, you’ll have to rely on your contractor’s workmanship warranty or call a new roofer to come out to reflash your chimney properly.
The second reason is the flashing around your chimney has worn down. All roofing materials reach the end of their lifespan eventually; roof flashing is no different.
Just like if it was improperly installed, water will get into your chimney if the roof flashing reaches the end of its lifespan or it’s damaged. When this happens, you’ll have to pay to have it replaced.
3 common types of roof flashing for a chimney and other problem areas of your roof
Now you know that roof flashing goes around your chimney to prevent a leak. However, there are different types of roof flashing that protect the chimney and other roof areas prone to leaks.
1. Step flashing
Step flashing is primarily used against the sides of walls and chimneys. It works by placing a piece of metal (flashing) under every shingle that’s installed right up against the side of a wall to block the water from running down into it.
That’s why the term “step” is used in step flashing. You do it step by step by installing a shingle, then a piece of flashing, then another shingle, then a piece of flashing until the wall is completely protected.
2. Apron flashing
Apron flashing is used at the base of a wall or penetration. It’s shaped like an L and can be up to 14 feet in length to fit the base of the penetration.
It’s also used around dormers to prevent water from getting into your windows.
3. Counter flashing
Counter flashing is used on walls and chimneys like step flashing. Unlike step flashing, the piece of flashing is sawed into an existing mortar joint, and the metal comes over the top of the brick.
Like step flashing, counter flashing is sometimes installed in a step-by-step method. But if you can actually see the flashing, it’s counter flashing.
Roof crickets are also needed to protect your chimney
If water doesn’t have a proper path down your roof to get to your gutters, it goes somewhere it shouldn’t and leads to a roof leak. A roof cricket helps avoid this problem around a chimney.
A roof cricket is a double triangle structure built behind a chimney to divert water around it properly. As water comes down your roof, it hits the cricket and splits down each side instead of hitting the flat wall of your chimney.
If you don’t have a cricket, water pools behind your chimney, and it could be costly to repair the damage once it starts leaking. To avoid this happening, the IBC (International Building Code) made installing crickets an actual building code starting in 2012.
According to the code, chimneys over 30 inches wide must have a cricket installed perpendicular to the roof’s slope. If you have a roof built before 2012, you might not have a cricket installed.
But when it’s time to replace your roof, a cricket needs to be installed to ensure your roof is up to code and prevent a leak. If you’re getting your roof replaced through homeowners insurance and have a code upgrade coverage policy, your insurance company will pay to have your cricket installed.
What causes a chimney leak?
After reading this article, you now know what goes around your chimney. Both roof flashing and crickets are crucial to preventing water from getting into your chimney and leaking into your home.
Remember, problems with the roof flashing can lead to a chimney leak. However, that’s not the only reason a chimney could be leaking.
To help you understand what’s causing your chimney leak, we wrote another article breaking down the common chimney leaks and who you should call when you notice one.
Bill Ragan Roofing has proudly helped homeowners in the Nashville area with their chimney and roofing problems since 1990. Whether you need repairs or a full roof replacement, you can count on our workmanship and attention to detail to give you a roof that lasts for decades. To back that statement up, we provide a lifetime warranty on our work.
Check out to learn what’s causing your chimney to leak when it rains.