How To Address Your Leaky Chimney This Winter Season

Is your fireplace slightly colder than the rest of your house? Do you feel a gentle breeze or chill when you walk past it? Is water leaking down the sides of your fireplace, walls, or ceiling?

You could be dealing with a leaky chimney. This occurs when there’s some sort of hole or opening in your chimney or fireplace that is exposing your home to the outside elements.

A chimney leak can be a major problem. Even a small hole or draft can invite in cold and flu viruses, encourage pests to make a home and lower the temperature of your house (which raises your energy bill). It can even cause water damage in your home if rain or snow makes its way through the leak.

The chimney is one of the only parts of your home that is directly exposed to the outdoor air, so you want to make sure it’s doing its job effectively. Learn how to address leaky chimneys to keep your home safe, warm, and comfortable this winter season.

Symptoms of a leaky chimney

How do you know if you have a leaky or damaged chimney? Here are some signs and symptoms that indicate you could have a problem on your hands:

• Visible water pooling in fireplace or flue
• Water or condensation in the firebox
• The sound of water dripping in chimney or fireplace
• Water stains on walls or ceiling near the chimney
• Musty odors near the chimney, especially after rain or snow
• Damaged bricks or stones
• Cracks in mortar or sealers
• Animal droppings, sounds, or sightings in the fireplace
• Visible debris, like leaves, in at bottom of the fireplace

Keep in mind that most leaky chimneys will only show small, subtle signs at first. Don’t wait until the water damage is extreme to take action.

Here are some ways a leak could be occurring in your chimney and what you can do about it.

Read: How To Prepare Your Home For Cold Weather

1. Close the Flue.

It seems simple, but a lot of us forget that the flue even exists. The flue is the latch that helps close your chimney, creating a barrier between the outside world and the inside of your home. When the flue is open, air can escape from your home (and vice versa); when the flue is closed, you shut off the airflow through the chimney.

When you’ve got a fire roaring, you want to keep the flue open to ensure the soot and smoke will leave your home. But you want to close the flue when the fireplace isn’t in use, so you don’t get any cold air, leaves, debris, water, or even pests making their way into your home.

If your flue is jammed or won’t close all the way, it could be clogged with soot or debris. You may need to call in a chimney sweep to help clean it out.

2. Check the Chimney Cap.

You also want to ensure that your flue has a chimney cap. This cap seals off the hole in your flue to block rain and debris, and it also prevents animals from making a home on top of the flue. If your flue doesn’t seem to be doing its job and you’re noticing leaves or animals in your chimney, you could be missing a chimney cap.

Chimney caps are especially important because they’re the first line of defense against debris. If your chimney gets clogged up it can’t do its job to release smoke from the fire out of the house. This can cause smoke to back up into the room, which can lead to CO poisoning, soot, and ash in the home, or other airflow problems when you light a fire.

We recommend investing in a stainless steel chimney cap because they are weather-resistant, durable, and long-lasting. They’ll do the best job to protect your chimney from intrusion while saving you money in the long-run.

Didn’t know you needed a chimney cap? Check out these 11 home goods you didn’t know you needed for the winter!

3. Check the Flashing and Crown.

The "flashing" is the material that surrounds the part of your chimney that sticks out of the house. It’s usually made of aluminum, and it covers the chimney and part of the roofing shingles. The job of the flashing is to seal off the roofline to prevent water from making its way down the sides of the chimney.

"Flashing" is usually covered in a waterproof tar or sealant to prevent leaks, but this can wear away over time. If damaged or corroded, you’ll start to notice leakage issues in your home. You may need to hire someone to replace or reseal the flashing if you’re noticing water drips down through your chimney.

Some chimneys have a “crown” instead of "flashing" (or they have both). Crowns are also used to divert water away from the chimney, but they’re typically made from cement or mortar as opposed to stainless steel. Cracks in the chimney crown can cause water to leak down into your fireplace and the surrounding walls. But you can usually seal this up with a crown sealer or plaster cement that’s made to withstand water and weather conditions.

4. Look at the stone.

Most chimneys are made of brick or stone. Either one has a unique set of concerns when it comes to leaking.

Bricks are most common for chimneys, but they’re also a highly porous material, meaning it tends to soak up water and moisture like a sponge. This can cause spalling, which is when the moisture soaked into the brick freezes, thaws, and freezes again. This can cause the brick to crack, peel, and deteriorate.

Damaged brick can occur both on the outside and inside of the chimney. So it’s important to consistently check your chimney for any broken or misplaced bricks. Learn how to replace spalling bricks with Family Handyman. After replacing any broken bricks, you’ll want to consider sealing the bricks with a water-based repellant to help block off the pores and prevent water seepage.  

Other types of stones used for chimneys are typically not as porous as brick, so they usually don’t have the problem of spalling. But mortar adheres better to brick than it does to stone. This means you could end up with small hairline cracks between stones that could cause leaking. In this case, you’ll want to reapply the mortar and protect it with a waterproof sealant.  

Conclusion

You want to spend your winter sitting by the fire with a hot drink and a good book. You don’t want to worry about your fireplace leaking or cracking.

A leaky chimney can be one of the sneakiest causes of damage to your home during the winter season. Even one small crack can cause water damage, infestations, clogs, and cold drafts. So make sure you take the time to check your chimney for cracks, leaks, and rubbish. If you feel a draft, notice water drips or damage, see debris in the fireplace, or hear animals—it’s time to take action.

A good place to start is by calling a chimney sweep. They’ll clean your chimney of debris and check for signs of damage, so you can have peace of mind this winter season.

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