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mold in crawl space

Crawl Space Mold and Your Health

While mold can easily find a home in your home's crawl space, it is very dangerous to your health and your structural supports. Learn how you can get rid of mold, treat areas affected by it, and prevent it from taking over your home.

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mold in crawl space

If you’ve discovered mold or mildew in your crawl space, you’re probably asking a lot of questions. After all, most people’s experience with mold exclusively has to do with food, which you can just throw out. Mold on the floor joists in your crawl space isn’t so easy.

Can Mold in Your Crawl Space Make You Sick?

It’s a good idea to tackle mold in your crawl space as soon as possible. That’s because mold of all types can make you sick.

Whether you know you have mold in your crawl space or you just suspect there might be a problem, you should take steps to handle it immediately. Let the experts at JES help with a free inspection to determine what mold crawl space problems you may be dealing with.

Crawl Space Mold

Problems, Causes, & Solutions

Some people wonder whether it’s even important to fix mold in a crawl space. After all, many people don’t visit their crawl spaces often, if at all. Can mold really cause that many problems?

Although mold may be present in a surprising number of homes, that doesn’t mean you can just ignore it. It’s important to fix any type of mold you’ve discovered in your crawl space.

Any Mold Can Cause Problems

Many people focus on especially toxic mold growths when describing the dangers of mold. It’s true: something like black mold in your crawl space can cause extremely serious health problems. However, that’s not the only thing that can cause health problems.

Even non-toxic types of mold in your crawl space can have health impacts. You may not even notice the health problems you’re having, but they’re still there.

When you fix the mold problems in your home, you’ll start functioning better. Even if the problems aren’t severe, it’s better that you’re not dealing with them. Healthiness matters, even if it’s a small improvement. 

Mold Rises Through Your Home

The argument that you never really visit your crawl space doesn’t actually hold up. You might not physically visit your crawl space often, but as a matter of fact, you’re dealing with your crawl space’s air more commonly than you might think.

Mold spores can become airborne, which means you don’t have to be in extremely close proximity to breathe them in. The “stack effect” means that air rises in your home. These two factors combined mean that you could be breathing in mold from your crawl space on a regular basis.

Even if you don’t often visit your crawl space, it’s important to fix issues down there. That mold can have health impacts even if you never see the mold in person. 

You’re Inviting Insects and Rodents Inside

You may not ever think about it, but mold is actually a great food source for insects. If you have mold or mildew in your crawl space, it’s likely you’ll start having mites and other insects as well.

When you have insects in your crawl space, you’re also inevitably going to find rodents in your crawl space too. This is especially true if you have open vents for your crawl space. Rodents are great at finding ways into a house.

Insects and rodents can both have health problems that can then transfer to humans. By not cleaning up the mold in your crawl space, you’re potentially inviting in further problems in the future.

What are the mold in crawl space health problems that can arise? This is definitely a big question many people ask, especially when they’re trying to discover whether or not they have mold without actually going into the crawl space.

The health impacts of mold can vary wildly. However, these are a few common health impacts you may experience from mold in your crawl space. 

Respiratory Issues

Your body isn’t meant to breathe in mold. Any type of additional particles in your air will eventually cause breathing issues. Especially when it comes to mold, those breathing issues can easily develop into a respiratory problem.

Among others, mold can cause sneezing, wheezing, difficulty breathing and sinus congestion. Regardless of how serious these problems end up being, they can at least be extremely frustrating.

Additionally, even mild respiratory issues can develop into much more serious issues. Your body expends energy when dealing with health problems. That can make you tired and lethargic all the time. 

Exacerbation of Allergies and Asthma

Does anyone in your home have allergies, asthma or a tendency toward getting sick? Crawl space mold can make those problems even worse.

If you already have allergies, asthma, or both, your body already tends to overreact to otherwise non-dangerous particles in the air. Mold tends to cause more problems than other particles. That may mean you can end up dealing with pretty serious respiratory problems.

Additionally, certain types of inhaled mold spores can actually cause brand new types of asthma and allergies. Dealing with mold as soon as you discover it can help you avoid developing these respiratory problems. 


At its worst, mold can actually be toxic itself. Mold excretes a certain type of compound called a mycotoxin, and higher levels of mycotoxins can cause dangerous and even potentially fatal complications.

Scientists hypothesize that all mold excretes mycotoxins. That means even relatively “benign” cases of mold in your crawl space can actually become toxic if it grows too much.

If you have a particularly dramatic case, like black mold in your crawl space, mold secretions can be even more dangerous. If you’re dealing with black mold in your crawl space, contact a JES expert immediately for more help.

Why does crawl space mold happen? There are a few reasons your home might develop mold or mildew in your crawl space. It depends largely on a variety of things that your home may include or that may be happening to your home.

If you’re dealing with a problem like mold on the floor joists in the crawl space, the causes could be varied. These are some of the most common potential problems. 

Open Crawl Space Vents

For a long time, people believed that crawl spaces needed to “breathe.” Because that was the prevailing wisdom, many homes now have open crawl space vents, which many homeowners believe makes the crawl space more healthy.

However, over the years, it’s come to many people’s attention that this isn’t the case. Because crawl space vents introduce external air, which is often high in humidity, into the area, this is a recipe for crawl space moisture.

When you have moisture in your crawl space, that frequently leads to crawl space mold. Open crawl space vents tend to cause this problem. 

Plumbing Issues and Leaks

Of course, another potential problem is much easier to discover. If you’re dealing with enough moisture that you have standing water in your crawl space, it’s likely that you actually have a leak dripping water into the area.

Plumbing problems can cause standing water in your crawl space. That may include flooding that happens in your home that then leaks down into the crawl space as well as plumbing problems that cause water to flow directly into the crawl space.

Regardless of the reason, standing water in your crawl space can introduce even more moisture into the area. That leaves you at a higher risk for mold crawl space problems. 

Flooding Outside and Wet Soil

This is especially a problem if you have a dirt crawl space. It’s more common for mold on the floor joists in your crawl space to form if the area is perpetually wet because it offers a more welcoming environment all the time.

Even if you have a brick or stone foundation, however, the wet soil in the area will expand and push against that foundation, potentially leading to cracks and breaks in the foundation. Almost inevitably, that means you’ll have water leaks.

If your area has recently dealt with flooding or an abnormally rainy season, the soil around your home could be holding more dirt than usual. It’s always a good idea to request an inspection just to be sure in these situations.

Clearly, crawl space mold is a problem. That leads to the question, how do you remove it? The good news is, there are a variety of options you can use to remove mold from your crawl space. A JES expert can help you discover the right option.

Although you might want to try and perform these fixes yourself, it’s typically a much better idea to leave it to the experts. When you consult a JES expert, you know you’re getting a fix that will actually remove the crawl space mold for good. 

Removing Water

First off, if you’re dealing with standing water, you have to remove it. This also means you have to shut off any significant sources of water, which may mean sealing open crawl space vents, fixing plumbing leaks or closing foundation cracks.

Of course, this isn’t the only thing you need to do. It’s important that you stop the problem at the root, which may take more digging than this. Installing a sump pump won’t necessarily fix the problem immediately.

However, a JES expert can help you remove the water from the area, which is definitely the first step. This way, you don’t have to purchase the pump and do the fixes yourself. An expert can help you through the process instead. 


If you have a dirt crawl space, you’re probably going to need to go through a process called encapsulation. This term describes the process by which you make sure moisture can no longer enter the crawl space as a whole.

Typically, encapsulation requires a thick barrier, which an expert can install across your entire crawl space. It’s not just a thin vapor barrier. It’s a very thick, hearty liner that can keep moisture out reliably.

Homes that don’t have a dirt crawl space might not need to go through this process. However, it’s still important that you seal off all potential entrances for water, which means closing open crawl space vents and fixing foundation cracks. An expert from JES can help you survey your crawl space and determine a way forward. 


Lastly, dehumidification will allow you to make sure the crawl space is actually dry. Leaving overt moisture in the area will continue the mold-growing process, and that’s never a good option. You need to make sure your crawl space returns to a low-moisture environment.

You’ll probably need to have a dehumidifier in your crawl space for a small amount of time regardless, to return the crawl space to a healthy moisture level. However, crawl spaces at high risk for moisture problems may need a dehumidifier at all times.

A JES expert will help you understand what you may need to do when it comes to dehumidifying your crawl space. Plus, this expert can direct you to energy-efficient dehumidifiers that won’t make a serious impact on your energy bill.

Let the Experts At JES Help You With Crawl Space Mold Problems

Clearly, there are a lot of reasons to take steps to avoid crawl space mold. Whether you already know you have crawl space mold, you think you might have mold in your crawl space, or you have moisture in your crawl space that forms a great habitat for mold, it’s a good idea to be sure.

You can never take too many precautions when you’re dealing with something that may impact you and your family’s health. All types of mold can have an impact on your health. That’s why it’s so important to handle mold as soon as you come in contact with it.

If you may be dealing with mold, you should request a free inspection from JES. Whether your worries are confirmed or it turns out not to be a problem, at least you’ll have an answer. That’s the most important part.

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