What Should I Do If I Think My Chimney Is Leaking?

by Claude Walters

Chimney leaks of any kind are easy to spot, because water damage around the chimney area will become visible more quickly than roof leaks close to your attic or eaves. This is because leaks near your chimney generally start causing your dry wall to peel or stain whenever it rains or snows. Chimney leaks don't always mean that your chimney itself is the culprit, so you'll need to do a little investigating to find out what's going on.

Check Your Chimney Cover and Flashing

Since your chimney is a direct route into your house, it needs quality protection to prevent water from getting in. This consists of a few different parts.

  • Your chimney cover, which is at the very top of the chimney's exit. It prevents animals and bugs from getting in, but also rainwater.
  • The chimney flashing, which is found where the chimney meets the roof, and is meant to create a watertight seal between the two.

If either of these are damaged or worn, it's sometimes quickly obvious due to peeling or cracking. To make sure this is fixed properly, you'll need to replace the flashing or cover rather than just using a bandage solution like caulk.

Check the Chimney's Outer Walls and Crown

Sometimes the problem can be as simple as a crack or hole somewhere on the outer chimney walls or the crowd, which is a concrete slab at the top. This is definitely a possibility if you have an older brick chimney. If there is visible damage there, the crown may need to be replaced, but unless the damage to the walls is severe you shouldn't need to rebuild the entire chimney.

If you suspect a leak here may be the cause, use a hose to spray water at the chimney walls while someone inside looks for water coming inside.

Look for Broken or Missing Shingles

Just because water seems to be coming down around your chimney doesn't mean it actually is. Due to your roof's angle, water leaking in can sometimes travel some distance before it drips down into your insulation and dry wall.

The first places you should look are your vents. These are prone to letting in water because the vents can crack and the flashing can wear faster, much like the chimney area. Look at each vent for damage. Once again, you'll need to replace damaged parts, not try to patch them up.

You should also thoroughly look at your shingles. If properly sealed, they'll prevent most leaks even if they're a bit worn. What you should look for are shingles that are missing, broken, or loose. Even though there are protective layers of flashing underneath, these shingles should be replaced immediately.

Make Sure You Have a Chimney Liner

Depending on what type of fuel you burn, a chimney liner is a necessity. If you burn gas for your fireplace, you will need a liner, which many older chimneys don't have because they were designed for burning wood.

The reason for this is because gas fumes carry a lot of moisture with them, and this can create condensation on the inside of your chimney. If the chimney interior is unprotected, that condensation can seep into the walls and start causing water damage. For more information, talk to a professional like A-1 Roofing & Siding.