11 Potential Problems With Water Seeping Through A Chimney Wall

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Water seeping through your chimney can cause some serious damage. Find out what the most common problems are and how to fix them.

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One of the things many homeowners don’t take seriously is the regular maintenance of their chimneys. Most only realize that they need a professional to inspect their chimneys when they notice water leaking through their chimney walls.

When water seeps through your brick chimney, it destroys paint, paneling, wallpaper, plaster, and every other type of finish. The leak can also seriously damage bricks by causing cracks and spalls. This can be difficult to handle and repairs can be costly, It also put you at risk of hazards like chimney fires if you don’t take action quickly.

In this post, we will discuss the problems with water seeping through a chimney wall, notable signs as well as some proven ways you can deal with this issue. Let’s get started.

1. Structural damage to the chimney

The brick and mortar used in making chimneys are quite durable but typically deteriorates with time and lets moisture get into the chimney system.

The moisture can evaporate during the warmer seasons and keep your chimney safe. In colder seasons, the water freezes and expands, causing cracks and damaging the masonry.

One of the most notable signs of water leaks due to damaged masonry is spalling bricks.

If you notice the signs of structural damage to your home’s chimney, do not ignore them even if the cracks in the brick and mortar are small. You can deal with the issue by using a brick sealant or talking to an expert who will recommend long-term solutions.

2. Leaks or water stains on your home finish

Water coming in through the chimney usually reaches the walls and damages various finishes like plaster, paint, and wallpaper. There are several ways you can tell if the water has gotten into the walls. The paint will start peeling off but prior to that, you will see discolored patches in the walls near the chimney area and the ceiling.

These patches are typically tan or yellow on white walls and ceilings and darken with time as more water gets into the walls.

If you have wallpapers on your walls, there will be small bumps and the wallpapers will eventually start peeling. You should seek professional help immediately after noticing water stains on your home finish.

3. Health problems

Many homeowners are unaware that water seeping through your chimney wall poses health risks.

When water leaks into the walls near your chimney system, the moisture it creates encourages the growth and spread of mold, a type of fungi.

Mold usually thrives in areas like attics, basements, and crawl spaces and you have probably seen or known it by its distinct odor.

When your chimney starts leaking, mold will likely begin to grow. Mold can spread fast to other damp areas of your house as they produce pores that can be transferred by water, air, and insects.

Mold causes respiratory problems such as wheezing, sneezing, coughing, and stuffiness.

People with mold allergies can develop issues such as eye irritation and rashes if they live in a house containing mold.

4. Chimney Flue Damage

Water coming down the chimney flue can cause air to be displaced and reduce its ability to vent properly. There are many downsides to having a chimney flue that doesn’t vent well. First, a Blocked chimney flue can reduce the efficiency of your gas and wood fireplace.

The chimney system needs enough draft to utilize oxygen and eliminate the toxic gases produced during combustion.

When water leaks into the liner, it dissolves the soot and creosote in the flue liner and destabilizes the air pressure leading to inefficiency in performance. This causes the dangerous by-products of combustion such as carbon monoxide to enter your house, leading to health problems.

Remember, carbon monoxide is odorless and invisible, so it’s important to fix a damaged flue liner as soon as possible.

5. Furniture and other home items damage

A chimney roof leak can cause a lot of damage to the items in your house. Mold thrives in damp environments so if you have a leaking chimney, the moisture will probably reach furniture and other items and facilitate mold and mildew growth.

Also, damp furniture in your home provides the perfect environment for wood-eating termites.

These termites will eat the wood and live inside it. If you don’t take precautions as soon as you notice these signs, the cost of replacing your precious household items will be huge.

6. Rotted wood

If the water coming down your chimney reaches the wooden items in your house, it causes rot. But how does this happen?

For rotting to occur, there needs to be moisture, warmth, oxygen, and a substrate (in this case, wood). Mold spores spread from other wet areas or items to the damp wood in the house and accelerate the rotting process. Replacing wooden items can be costly if you do not deal with the problem early enough.

7. Moisture Problems

A leaking chimney means more water enters your house’s ceiling and walls, leading to an unpleasant musty or earthy smell.

The odor is usually caused by mold growth in some areas of your home and can cause nasal irritation and other health issues.

Moisture also mixes with creosote, a black substance made up of various chemicals that usually build up in the chimney flue when some of the smoke remains in the chimney.

The resulting mixture is not only toxic but also highly flammable.

8. Chimney Fire risk

Chimney fire risks increase if you have a leaking chimney.

Most chimney’s flue liners are made of clay so when there is water coming down a chimney, it could get in the liner and mix with creosote and form a combustible substance.

The moisture usually causes cracks in your chimney liner and because of the flammable substance inside it, it can easily catch fire. The fire in the flue liner can easily spread to your house and destroy your household items.

9. Metal chimney rust

Water that gets into your metal chimney causes rust or corrosion leading to issues such as gas leaks and equipment malfunction.

Even if you are using stainless steel, it can still rust because of the combination of water and creosote/soot in the chimney liner.

Regular inspection will help you keep your chimney in excellent condition.

10. Water condensation in the fireplace

Your fireplace is prone to condensation if there is water dripping into the fireplace. This negatively impacts the chimney masonry as the mortar becomes weaker and the bricks begin to spall.

11. Energy efficiency

Keeping your energy bills low means you save more cash for other things. Water leaks in the chimney usually cause improper functioning of heating equipment in your home, which is likely to increase your energy bills.

In addition, the repairs can be costly especially if you wait too long before contacting a chimney repair expert.

Tips to prevent water from coming in through the chimney

Here are some tips to help you fix a leaking chimney:

  1. Inspect the roof and seal any cracks or holes that may allow water to seep in
    A waterproofing sealant can provide a quick fix to a leaking chimney. Note that this should only be a temporary solution as larger cracks and leaks require more than a sealant.

  2. Have the chimney cleaned and inspected annually by a professional chimney sweeper
    Creosote buildup block and prevents your chimney from venting properly and puts you at risk of chimney fires. Therefore, regular inspection and cleaning are necessary.

  3. Make sure the damper is closed when the fireplace isn’t in use
    After you finish using your fireplace, the heat generated keeps your house warm. If you leave the
    damper open, the warm air will escape.

  4. Check if your chimney cap is missing or damaged
    If your chimney cap is damaged or missing, rainwater and other debris will enter your chimney. Fixing a chimney cap may be all that’s needed to stop water leaking through your brick chimney.

  5. Make sure the flashing around the chimney is properly sealed
    The flashing forms a seal between your roof and the chimney so if it is damaged, water will enter your chimney.

    The flashing is a vital part of your chimney system so it’s better to get a professional to look at it than fix it yourself if it is damaged.

  6. Repair any leaks in the roof or walls as soon as you notice them
    Leaks in your roof or walls can allow water into your chimney so fix them quickly before they become bigger.
  7. Use a moisture meter to determine if your chimney is leaking
    At times, finding leaks can be a challenging task. Using a moisture meter is a great way to determine whether your chimney is leaking.
  8. Keep your gutters clean and free of debris
    Your home’s gutters collect debris over time and if you don’t remove them, they will be unable to drain water properly.

    Ensuring your gutters (especially those near chimneys) are debris-free prevents roof or chimney leaking issues.


As you can see, you can easily deal with problems with water seeping through a chimney wall using tips like repairing your chimney cap and sealing the chimney flashing. Since doing all this by yourself can be challenging, get in touch with a professional chimney sweep.

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Thomas Green

Thomas has worked in the Chimney & Fireplace field for over 12 years. He is an expert in his trade and loves to help People with their needs. Thomas Write helpful articles so that homeowners can make the most informed decisions about their fireplace and chimney.