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7 Reasons Why Fireplaces Leak and How to Fix It

It’s been raining a lot recently, and my parents asked me if they should be worried about rain getting through their chimney. I had an idea of how chimneys keep the rain out, but I wanted to give them a full answer and what to keep a lookout for. So, I did some research to find out why fireplaces can leak and what can be done about it. Here’s what I found.

Fireplace leaks most commonly come from the wear and tear of the chimney. This includes leaks in the flashing, chimney cap, and mortar. While fixing a leaky fireplace or chimney can be involved, most issues require a professional to fix.

Here are the most common reasons why fireplaces leak:

  1. Flashing
  2. Chimney cap
  3. Structural damage
  4. Old mortar
  5. Outdoor Siding
  6. Unrelated damage
  7. Wear and tear

When it comes to leaky fireplaces and chimneys, some causes are easy fixes, while others might require professionals. Read on to learn why fireplaces leak and how to fix some of the most common issues.

7 Reasons Why Fireplaces Leak When It Rains

For the majority of fireplace leaks, most circumstances will result from problems with your chimney. However, this is not always the case. Regardless of why your fireplace is leaking, there are different ways to fix the problem. But first, let’s learn about how exactly these problems occur.

1. Flashing

One of the most common pieces of evidence you might see that shows a leaky fireplace is water in and around the structure. Frequently, this can be a problem with your flashing. Flashing is the protective layer – usually made of aluminum or steel – that, when paired with tar, serves as a sealant that secures the base of your chimney to your roof.

Since a material like aluminum is not necessarily an ideal piece to use, it may not hold up forever. But, it serves the purpose of protection for a certain time while also allowing flexibility for different temperatures, weather conditions, etc. Over time, or because of severe weather, the flashing around your chimney base can become faulty.

If this flashing seal becomes damaged or detached in any way, you run the risk of letting water through the chimney base, down your fireplace, and into your home. Damaged flashing is not entirely difficult to spot. Signs that you might be dealing with flashing damage include:

  • Excess amounts of water dripping into your fireplace
  • Water bubbles forming in your ceiling
  • Water bubbles and damage to the wall surrounding your fireplace
  • Noticeable damage to the flashing around the base of your chimney

How to Fix It

If you have problems with the flashing around the base of your chimney, it might be an easy fix. With slight damage to your flashing that might be letting water seep into your fireplace and walls, the hole can usually be filled with some sealant. Small holes and cracks are quick fixes for a leaky fireplace.

The best way to do this is by smoothing out the metal of your flashing with sandpaper and filling the hole with a small amount of wet cement. When the cement dries, it acts as a strong barrier to close up the hole. This is one of the easiest ways to fix a problem with your leaky chimney or fireplace.

In other circumstances, the damage might be more severe. If you have entire sections of your flashing wearing or fraying away, they might not be repairable. In this case, you likely need to replace your entire chimney finishing. Trying to repair significant damage can lead to further problems, and you might not guarantee that you repair all parts of the finishing.

If you do decide to have your entire finishing replaced, your best bet is to call a professional. After all, you want to make sure that the job is done correctly, especially when dealing with a problem that allows water to flow into your home. Luckily, flashing damage is not extremely detrimental.

2. Chimney Cap

chimney professional installing a chimney cap

A chimney cap is a metal piece that goes on top of your chimney to keep animals and, ideally, water out of your fireplace. You do not have to have a chimney cap, but most people do. If you do not and notice that there is water in your fireplace, this is probably the reason.

If you do have a chimney cap, but you notice a leak in your fireplace, it might be that your chimney cap is damaged. If any part of the solid top or mesh siding develops large holes, water can get through a chimney cap fairly easily, which can be challenging to spot.

Sometimes, your chimney cap might just wear out over time; other times, the problem might be caused by birds, squirrels, or other animals around your chimney or severe storms that cause damage. If this happens, it can be not easy to recognize. Since the chimney cap is at the very top of the chimney, it might not be an easy problem to spot.

A less common problem you might face is if your chimney cap does not correctly fit the top of your chimney. If it does not create a tight enough seal, it will not do you any good. If you get a chimney cap installed, you need to make sure it is the right fit. If you do not, it does not really serve its purpose.

How to Fix It

If you think your chimney cap might be the cause of your leaky fireplace, you should first make sure that the chimney cap fits into your chimney correctly. After that, check for any damages that might be causing the problem.

Repairing or replacing a chimney cap generally takes quite a bit of experience, so trying to do it yourself may not be your best option. You will need to get on your roof, remove the chimney cap, and install a new one or even create your own cement mixture that will act as a basis for your new chimney cap. 

It can take a lot of work, so you should consider getting a professional over to survey the damage and at least allow them to give their input. Particularly if you have little to no experience, letting a professional take care of the problem can help you avoid further problems in the long run.

3. Structural Damage

Structural damage in and around your fireplace or chimney can pose major threats that can allow water into your fireplace. Whether it be from wear and tear, severe weather, internal or external, or something else, any structural damage is dangerous not just for allowing water in but also several other risks.

Any significant cracks or holes in your fireplace or your actual chimney can definitely allow large amounts of water in. What makes matters worse is that these damages can be complicated to find, so you may struggle with a leaky fireplace for some time. Structural damage is extremely important to keep an eye on.

Besides the risk of a leaky fireplace, structural damage can raise the risk of many other problems:

Minor damageSevere damage
Leaky fireplace or a dysfunctional fireplaceStructural damage can cause a collapse onto your home, ventilation problems, or irreparable or expensive damages

How to Fix It

As you might have guessed, fixing structural damage to your fireplace or chimney is often a necessity. Yes, this is an article focused on leaky fireplaces, but the damage from the structure can prove much more detrimental than a pressing leak.

Fixing structural damage to your fireplace or chimney is going to require professionals equipped with the necessary scaffolding, tools, and experience to fix this problem. Regardless of why it needs to be fixed is irrelevant. In almost every case, this is probably not something you can do on your own.

Concerning only a leaky fireplace, structural damage can still be a grave matter. Since the damages can be so difficult to find, failure to fix them can cause excess amounts of water to find its way through your fireplace and into your home.

4. Old Mortar

a chimney with old and cracking brick and mortar

The brick and mortar that your chimney is made of can only last for so long. Over time, deterioration is inevitable, and these damages can let large amounts of water leak into your fireplace. Even tiny cracks or crevices in mortar can fail to hold up.

Once the mortar holding your chimney bricks together starts to deteriorate, it does not do an outstanding job of keeping water out. If you notice that your fireplace is leaking, old mortar is a common problem that is typically easy to spot.

If you notice areas around your chimney that look worn out or excessively wet, it might be that your mortar’s lifespan is coming to an end. However, not all hope is lost. Just as the other causes of a leaky fireplace, this is something that can be fixed.

How to Fix It

As this is generally a complicated exterior problem, it is also going to require professional help. Repairing old mortar or replacing whole sections of bricks takes a lot of experience, so make sure that you contact a professional.

Failure to have old brick and mortar replaced will risk large amounts of water leaking into your chimney as well as further damage that can deteriorate the entirety of your fireplace and chimney. Not to mention, weak bricks can further add to the risk of structural damage.

5. Outdoor Siding

Another problem that might be causing your fireplace to leak could result from damage to the siding of your house where your chimney is connected. It does not always have to be a problem specific to your chimney or fireplace themselves; anything connected or in the near vicinity can cause problems as well.

Worn or damaged exterior walls connected to your chimney can become detached and allow openings for water to leak into. Once water finds its way through, it can go directly into your fireplace. Since siding is not always made of the most lasting material, this is a common problem for why a fireplace leaks.

This problem is not typically observable from the inside of your home. You may not notice the openings in your fireplace that are allowing water in. Usually, however, you will likely be able to see cracks or other damages on the exterior siding of your home.

How to Fix It

As this is yet another problem dealing with structural damage, you might consider calling a professional to check it out. On the other hand, perhaps the damage is not too severe.

If you recognize a small hole or crack in your siding, it might be an easy fix. Keep in mind, any type of siding that is not brick will likely be made of some sort of vinyl, wood, or strong plastic. If this is the case, the process of repairing an individual piece of siding is relatively simple.

You can patch holes or repair siding pieces in no time, so you should not have any trouble if this is the problem. As said before, however, major damage to siding might require professional work. Particularly if the siding has been damaged for some time, it can be challenging to take care of your problem on your own.

6. Unrelated Damage

If your fireplace is leaking and you just cannot seem to find out why, it might not be a problem with any area in or around your fireplace or chimney. Roof damage is known to cause a leaky chimney, as well as other miscellaneous causes.

If your roof’s shingles or structure have been damaged, this can allow water inside that will seep through your attic and into your walls. If your fireplace happens to be in this area, it will appear that your chimney might be leaking.

Unless you have water damage in other places around your walls or ceiling, this can be a tricky problem to spot. If you do not see anything wrong with your fireplace or chimney, you should take a look at the condition of your roof. Damages may be easier to spot when you observe from the outside.

Other problems unrelated to your actual fireplace might include:

  • Other leaks from your house’s exterior and into your walls: Any type of leak can find its way to your fireplace.
  • Leaky pipes whose water finds its way into your fireplace: Nearby, leaky pipes can seep through to your fireplace.
  • Damage from underneath your home (a very, very rare occurrence): Underwater pipes, flooding, or moisture underneath might pose a threat.

How to Fix It

Repairing roof damage is not typically too severe of a matter, but it will still likely require professionals. Unless you have experience replacing pieces of a roof, it is not such a good idea to climb up there and try to solve the problem yourself.

Luckily, roof repair is usually a quick fix, and you will not have to worry about further damage once the matter has been dealt with. However, it is important to recognize problems with your roof early on to avoid additional leaking.

Other miscellaneous problems might need a different approach. For example, a leaky pipe might need the assistance of a plumber.

7. Wear and Tear

damaged bricks on a smoky chimney

Normal wear and tear can cause a leaky fireplace; it does not always have to be the result of damage. However, in both cases, the repairs can be similar. Wear and tear can be more severe, though, because it can sneak up on you.

Both wear and tear and damage can cause the same problems, whether it be a cracked chimney, dysfunctional chimney cap, or anything else. The effects of these problems separate the two causes from each other.

The difference between wear and tear and damage is that the damages can be more difficult to spot with wear and tear. If you do not suspect any damage, you might not notice deterioration over time. Because of this, when your chimney starts leaking, it might take a lot of time to spot the problem. 

Also, wear and tear deterioration happen slowly, so when you do notice them, the consequences can be more costly. Trying your best to catch the deterioration early on will help you in the long run.

How to Fix It

Deterioration from wear and tear can be repaired just like any other damages, but there are steps to take to avoid problems as best as you can. The first thing to do is take care of your fireplace and chimney.

Regular upkeep is vital to ensure that your fireplace and chimney stay intact and functional. Keeping an eye on the evidence of any problems is a must. Failure to do so can result in costly consequences.

How to Tell If Your Chimney Is Leaking

There are multiple ways you can spot signs of a leaky chimney. For starters, any evidence of water in your fireplace is an excellent place to start. However, it might not be as simple as that. Below are some of the main signs that your chimney is leaking. Most of the signs are relatively clear, but some might not be as apparent.

Wet Fireplace

If you notice water or condensation inside your fireplace, chances are that you might have a leak in your chimney. As is evident, any leaks in your chimney will pass water down into your fireplace. This is one of the easier signs of a leaky chimney to spot. 

There is no other explanation for water in your fireplace besides the existence of deterioration within your chimney. Even small amounts of water are possible signs of a leak in your chimney. Condensation on the walls in or around your fireplace is also telling signs.

Water Stains

Water stains are another telling sign that you might have a leak in your chimney. If you notice water bubbles or wet spots on your walls or ceiling around the area that your chimney is in, it could mean you have a leak. 

Since the water damage is not directly in your fireplace, your first thought might not be that your chimney is leaking. However, it is definitely something you should look into. Any type of water stain around your chimney and fireplace is cause for concern, regardless of whether it is related to your fireplace.

Foul Odor

If you notice a musty smell around your fireplace, this is another probable sign of a leak in your chimney. Particularly during inclement weather, condensation build-up can cause an unpleasant odor in the area around your fireplace.

Again, this might not be the easiest way to spot a leak in your chimney, but if the odor is surrounding your fireplace, there is likely a problem with your chimney.

Damaged Chimney

A cracked chimney is not always a sure sign that water is getting through, but it should be examined. Whether it is on the interior or exterior of your chimney, a crack can cause future leakage into your fireplace.

Damage to your chimney might also include holes or damp spots. Any sort of deterioration that is not sealed can allow water to pass through, so it is important to keep an eye on your chimney.

Can Water Leak Through Brick Chimneys?

Over time or due to damage from weather, brick chimneys can get leaks. If the brick and mortar are worn down, water can seep through even the most minor cracks and find its way down into your fireplace. 

Signs that water is leaking through your brick chimney are the same ones that have been discussed previously in this article: cracks, flashing damage, wet spots, etc. There is no question that brick chimneys can last for quite some time, but eventually, they may not prove invincible.

What to Do If Your Chimney Is Leaking

a chimney with a leaky roof

If you find that you have a leak in your chimney, there can be many ways to go about it. As stated above, different circumstances call for varying fixes; some problems are quick and straightforward, while some need the help of professionals.

Can You Do It Yourself?

For small holes in your chimney, damaged chimney caps, flashing problems, and other small damages, problems like these can be DIY projects. With a bit of cement or other sealants, you can close up the openings yourself.

Professional assistance is highly recommended for larger-scale damages, especially working up high or on a roof to repair your chimney. Some other instances, like leaks in walls, are not so much dangerous as they are necessary to have experience. If you do not think you can fix the leak with sealant, your best bet is to call for help.

How to Do It Yourself

If you plan on fixing a leak in your chimney on your own, there are a few steps to follow to make sure you accomplish your goal. If it is a small problem, you should not have too much trouble with the process.

1. Observation

If your chimney or fireplace is leaking, you first need to examine the area in and around them. Whether you start with the interior or exterior, make sure that you are making careful observations.

You might not always know precisely what you are looking for, so this can take some time. Watch out for cracks, holes, or sections of your fireplace or chimney that appear to be damaged or deteriorated in any way.

2. Do Your Research

Once you have found what has caused the leaking, you should do some research and find out the next steps to take. You do not want to try and fix the leak without any prior knowledge.

Find out what materials you are going to need. If it is a small problem, you should not have to get too much. Next, learn how you need to use the materials to fix your leak.

3. Fix Your Leak

After you have found the problem and learned how to fix it, get to work. For small cracks and holes, applying concrete is as simple as it gets. For larger cracks and damaged flashing or chimney caps, you might have to do a bit more work.

If you find it difficult to fix the leak in your chimney or fireplace, you might not need to continue repairing it on your own. In this case, it is a good idea to get professional help.

Who Do You Call?

Perhaps the most reputable field of workers to call for chimney leak problems is a local roofing company. Aside from fixing shingles, roofers have experience with patching leaks, repairing damage to bricks, fixing chimney caps, and more.

In most cases, roofers will have no problem fixing your leaky chimney. Unless the leak has led to other damages in your home, you should not have to worry too much about the roofers getting everything back to normal.

Final Thoughts

After doing this research, I was able to give my parents a full answer on leaky fireplaces. So, while they currently don’t have a leaky chimney, they now know what to look for and what the fixes will involve.

Overall, there are different paths to take to fix these various leaky problems. Some can be accomplished on your own, while some require professional roofers. Whatever the case may be, as long as you catch problems that cause leaks in your chimney and fireplace early on, they should not cause too much trouble.

Need More Help?

You can always ask us here at Fireplace Tips, but you should know the other resources available to you! Here are the resources we recommend.

  • Chimney Safety Institute of North America (CSIA): The CSIA is your BEST resource for fireplace and chimney safety at home. They’re a non-profit governed by a volunteer board of directors dedicated to the education, training, and certification of chimney and industry related professionals.
  • Self-Sufficiency and Off-Grid: If you’re like me and passionate about off-grid and self-sufficiency, see my number 1 resource—Abundance Plus. Check out their Frugal Homesteading Course on growing 90% of your own food. Get 7-days free and 10% off with the code: TYLER10