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Musty Basement Smell?

Musty Basement Smell

Dampness, cracks, and waterproofing issues can cause serious basement moisture problems, which can themselves lead to mold and other health concerns.

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Musty Basement Smell?

Do you have a musty basement? That musty smell means that you have mold growing in your wet basement. And we all know that mold leads to serious health problems. But there’s good news: you can get rid of the mold and that musty basement smell for good!

If you’ve ever gone into your basement, there’s a possibility you’ve been confronted by a gross, stale odor that many people describe as “musty.” This smell can be very confusing and very worrying because you don’t often encounter that type of smell anywhere except your basement. What is it? Should you be concerned about it? The smell means you have mold in your basement, which can be a serious problem. Here’s how to handle that problem.

Do These Basement Photos Look Familiar?

Dampness, cracks, and waterproofing issues can cause serious basement moisture problems, which can themselves lead to mold and other health concerns. The good news is that you can fix it. You just have to know how.

Do You Have Any of These Basement Moisture Problems?

Basement moisture problems can manifest themselves in many ways. Do any of these photos look familiar? They can all indicate basement moisture problems in different ways.

The reason for the musty basement smell can be elusive at first, largely because most people never experience this smell outside of the basement. There are typically three main things that have to happen for a musty-smelling basement.

Organic Material 

The first necessity is some kind of organic material. This can come from just about anywhere; wood, which many homes use for at least part of the floor joists, is an organic material. Many insulations also count as organic material, and if you don’t take good care of your basement, it’s possible the insulation could come out of the walls and ceiling.

Although you can clean up some of this organic material, like the fallen insulation and anything else that has fallen into the basement in some way, you can’t get rid of all of it. If you have wood as part of your foundation, for example, you’re never going to be able to get rid of the organic material in your basement. The good news is that this is only one part of the equation.

High Relative Humidity 

The next necessary thing is high relative humidity. Relative humidity is a measure of how much moisture is in the air proportionate to how much moisture that air could hold maximum. For example, if the air is at 70% humidity, that means the air is currently saturated with 70% of the moisture it could hold at the most.

This is an important measurement because once air gets to 100%, that means it’s as saturated with moisture as it can possibly be. If the air goes over 100%, that excess moisture has to go somewhere, and most commonly it comes out as condensation on a cool surface. High relative humidity is a necessary part of the equation because it’s the only way you’ll be able to get the next part.


Most of the time, when you’re smelling a “musty smell,” the majority of that smell is just mold. Mold forms when organic material and high relative humidity come together. Mold typically requires a relative humidity level of at least 60%, but beware: even if the rest of your basement has a relatively low humidity level, mold can grow on and around water spots, including condensation spots.

Mold is typically recognized as a danger to humans. Although it’s very rarely toxic, it can certainly cause allergic reactions and respiratory problems, which can be frustrating and upsetting to anyone who doesn’t know why it’s happening. This mold might not kill you or even seriously harm you, but it will have a dramatic impact on your quality of life.

This is the most important reason that if you smell a musty smell in your basement, you need to seek help from a basement waterproofing expert immediately. Mold isn’t something you should just leave to its own devices. If you can remove it from your basement, you’ll be more well-positioned to fix any problems you were experiencing due to mold.

Now that you know what the musty smell is, many people will turn to the next natural question: How can you get rid of it? Fixing your musty-smelling basement is not easy. People have many uncertain answers to this question, and some of them don’t even work.

Bleaching the Basement 

A method some people recommend is simply using bleach. Bleach is known to be good at killing mold, but there are many things you need to think about when you’re trying to remove mold and mildew from your home. Simply spraying your basement mold areas with bleach doesn’t really do anything; if you do it improperly, it can cause even more health risks to you. 

It’s true that bleaching may be an important part of a mold removal process. However, mold removal is more than just spraying bleach on something. It’s a complicated and messy process that might be very difficult for you to achieve. When you’re dealing with mold, skip the bleach and leave it to the professionals instead.


A dehumidifier can certainly be a useful tool during the mold removal process; after all, if excess moisture is part of the reason the basement smells so musty, surely a dehumidifier, which removes excess moisture, can help with that. The problem is not with the use of a dehumidifier as part of the process of removing excess moisture from your basement area, however. The problem comes when individuals try to use a dehumidifier as the only method of fixing things.

The right way to use a dehumidifier is as a secondary part of the process. You should never use a dehumidifier as the main portion of the process because a dehumidifier isn’t built for that type of moisture removal. If you use a dehumidifier to help with your basement’s musty smell, only use it in conjunction with other methods of removing moisture and avoiding it in the first place.

The encapsulation process can be confusing if you’ve never gone through it or tried it out at any point. Here’s how the encapsulation process for your basement will work once you’ve contacted a JES basement waterproofing expert and started the process. 

Remove Existing Debris 

The first step is to remove any and all existing debris. There are many things that could be “debris” in your basement. For example, if you’d tried to lay down a vapor barrier before but it was thin and flimsy and tore apart, you’ll have to remove that before you can proceed with the encapsulation process.

Otherwise, that debris is just going to stay there and collect bacteria, which isn’t good for anyone. 

This debris removal process can be tricky if you don’t have the right equipment. After all, most of the debris will probably have some form of bacteria, mold, or mildew, which means you can’t just pick it up with your hands. A JES waterproofing expert will be able to give you more information about how they can help you remove this debris and make it easy to move to the next step.

Add a Vapor Barrier 

This next step is to add a vapor barrier that truly works. This isn’t a flimsy 6mil vapor barrier or a thin piece of plastic sheeting. The vapor barrier under your home should be a strong, thick vapor barrier that resists any attempts from moisture to come through. Additionally, it should stand up to light movement on top of it, as someone might need to come in for any number of reasons.

The vapor barrier JES uses is a 20mil CrawlSeal vapor barrier. Although it might seem like overkill to use a 20mil vapor barrier in the basement, which is often only lightly trafficked, it’s actually an important part of the process. You should absolutely opt for the strongest vapor barrier available in this context.

Close Crawl Space Vents 

The next step is to make sure you close all crawl space vents. Because you’re dealing with a musty basement, you might not have any of these vents; after all, they’re called “crawl space vents” because they’re usually in crawl spaces instead of basements. However, some basements have crawl space vents because people once thought they would be helpful.

Of course, now most people know better and are aware that crawl space vents do more harm than good. If you have open crawl space vents in your home right now, consider putting crawl space vent covers over the vents, regardless of whether they’re situated in a crawl space or a basement.

Include a Dehumidifier If Necessary 

Although a dehumidifier shouldn’t be your primary method of handling condensation, that doesn’t mean you should completely remove dehumidifiers from your list of tools. In fact, a dehumidifier can be an amazing tool to make indoor humidity easier to manage. It’s just all about whether you’re using it in the right way.

Remember that your dehumidifier should be strong enough to maintain a steady level of humidity at whatever level you specifically decide. Many people decide they want dehumidification options in their crawl spaces but don’t look into whether the dehumidifier will actually work. With the JES dehumidifier, you can rest assured that your dehumidification strategies will make things easier to handle for you and anyone else living in the home.

Can I fix my Musty Basement?

Venting your basement will only make the problem worse. By opening your basement windows you’re letting more humidity in, which is the source of your musty basement smell.

And don’t assume that bleaching down your basement will get rid of the musty smell. Mold removal is dangerous and messy! Don’t put your health at risk trying to get the mold out of your musty basement.

“Venting your basement will only make the problem worse.”

What Do I Do Now?

Our professional basement waterproofing specialists will perform an in-depth investigation of your musty basement. When they find the source of the water, they’ll work with you to create the best solution for your home.

And if they find that your musty basement is something that you can fix without professional help, they’ll tell you.

Letting the Experts Take the Lead

Even if you have a lot of knowledge about the smell of musty basements because you’ve read about it on the JES website, that doesn’t mean you have all the knowledge you necessarily need to fix the problem. In fact, it’s likely that you don’t have the information you need to assess the situation, come up with a plan, and then execute that plan in your own basement.

The good news is that JES basement waterproofing experts do have that knowledge. Instead of trusting your own intuition and knowledge of basement waterproofing processes, you might as well trust the people who have spent years learning about and working with moldy and moisture-rich basements. Request an inspection and you’ll be able to get a concrete answer about what’s going on with your musty-smelling basement.

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