Foundation Vents – Why They’re Bad for your Crawl Space

Learn more about why crawl space vents are bad for your home, and what you can do to address these issues.

open vent in crawl space

Does Your Crawl Space Need Vents?

Many years ago, people believed that foundation vents were an important part of creating a crawl space. The idea was that the crawl space needed to breathe, and vents were the best way to let that happen.

Unfortunately, this prevailing theory ended up being false. Now, many people have house foundation vents that are actually doing them a disservice. In fact, even the best foundation vents can actually lead to serious crawl space issues.

If your home currently has a foundation vent system, you probably need expert help determining how to seal them. Replacing crawl space vents doesn’t need to be difficult. Read on to learn more about crawl space vents, and contact JES for help with yours.

Foundation Vents Let Moisture In

The truth is, foundation vents simply let moisture into your crawl space. Even if you’ve installed foundation vent wells and looked for the best foundation vents available, you’re still going to have moisture issues.

Why is this? When you understand how crawl space foundation vents work, it’s much easier to get an idea of why moisture tends to coalesce there.


Learn more about humidity in your crawl space.

This is the key to understanding this concept. Unfortunately, it can be pretty confusing. The gist of the matter is that warmer air can hold more water than cooler air. When cooler air starts to hold too much water, that water vapor coalesces into general water, which has to collect somewhere.

Essentially, that means a crawl space sitting at 65°F can hold substantially less water vapor than an outdoor area at 95°F. If the warmer, wetter air comes into contact with the cooler, drier air, that water vapor will collect somewhere in your crawl space.

You can do calculations to determine exactly when the water vapor will start to condense, but for these purposes, you just need to know that it will. When the condensation forms, you’re going to start having moisture problems.

If you have crawl space vents, even the best crawl space vents out there, they’re going to let in humidity. After all, that’s sort of the point. The idea is to let outside air in so the air doesn’t become stale and stagnant.

However, while inviting in fresh air, crawl space vents also invite in humidity. That means you’re going to start seeing condensation pretty quickly.

It’s important to realize that even automatic crawl space vents have this problem. It doesn’t matter if you get to choose when the vents are open. As long as the vents have the option to open, you’re going to invite in moisture every time you open them.

Your crawl space rests under your home, typically in the dark and underneath the surface of the ground. That means it’s often very nice and cool in the crawl space.

This isn’t inherently a bad thing. In fact, it can be a very good thing. It only becomes a bad thing when you introduce warmer air through a crawl space vent.

Because of how relative humidity works with cool air, you’re always going to have the problem of condensation when you have crawl space vents. A crawl space vent well is only going to keep out already-condensed moisture. It’s not going to do anything about the new moisture this process is constantly creating.

The Perils of Crawl Space Moisture

It’s clear that no matter what, your crawl space vents are going to invite in moisture. The next question is, why does it matter that there’s moisture in your crawl space? Can I just install replacement foundation vents and call it a day?

Unfortunately, moisture is the number one enemy of your foundation and your home structure. It can cause a whole host of problems, including but not limited to these issues.


Excessive moisture and humidity can lead to a variety of problems. Learn more here.

In moist environments, you’ll find that mold, mildew, and wood rot grow quickly. Mold and mildew especially like to grow on any surfaces available. The moisture in the air also makes a perfect environment for wood rot.

These aren’t just gross. They can also be very dangerous. You don’t want these things in your home or in your air.

Left untreated even for just a few months, mold and wood rot can quickly start to eat away at your home foundation. Plus, they can cause serious health concerns for anyone living in the home. 

Another reason you don’t want mold, mildew, or rotted wood is that it pulls in insects. Bugs love to eat mold and rotting wood, and the moisture provides an easy way for them to drink.

If you’re dealing with bugs, you’ll probably find that you soon start dealing with mice. Rodents eat bugs, and they can also come in through your foundation vents, even if you’ve tried to learn how to install foundation vent covers.

Soon, you’ll find there are plenty of little creatures down in your crawl space. Before you know it, these creatures can be making a serious impact on your home’s stability and foundational strength. 

It takes a lot more energy to make humid air feel cool again. As the humidity rises in your crawl space, it’ll evaporate again into the air, then rise up through the rest of your home. That means everyone living in the home will start to feel it.

It’s common for people to feel much more affected by the heat when the warm air also contains a lot of humidity. That means people will want to crank up the air conditioner, which can be hugely impactful on your energy bill.

With significant moisture in your crawl space, you may be spending a significant amount more on your energy bill than you need to. Fixing these problems will let you reduce your energy bill, potentially saving you money every single month.

Crawl Space Water and Waterproofing 

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DIY Sealing Foundation Vents

It’s difficult to make the decision to pay for home repairs, even when those repairs could save you money. You may have looked into how to install crawl space vents and how to install foundation vents, so why not look into information regarding the opposite?

The fact is, you probably shouldn’t try to encapsulate your crawl space on your own. It may seem like a good way to save some money, but here are some reasons to leave it to the experts. 


Learn why it's so important to work with crawl space professionals when it comes to repairs in this sensitive area of your home.

One of the most important reasons you shouldn’t try to do this on your own is that the foundation of your home is a very delicate thing. If you mess something up, it could spell disaster.

The foundation of your home is just that: a foundation for the entire thing. The last thing you want to do is change something that has a serious impact on the rest of your home.

This is why you need to trust a foundation repair expert from JES. A foundation repair expert can help you fix your crawl space without potentially harming your home in the long term.

With something this important, it’s not enough to just halfway fix the problem. You need to make sure you’re actually fixing the problem, not slapping a bandage over the top.

Actually fixing the problem will make sure it goes away. It also makes sure that your problem doesn’t multiply behind your back. That way, you don’t have to worry about whether or not you actually tackled the issue.

An expert will help you get to the bottom of the problem, then eradicate the problem entirely. When you have a JES professional working on it, you know you can rest easy. 

No matter how much faith you have in your ability to do home repairs, it’s simply not your specialty.

A foundation repair expert knows exactly what they’re doing because it is their specialty. You don’t have to try and learn something new, then hope you’re able to execute it properly. You can just trust that the foundation repair expert has the knowledge and experience to get the job done.

Don’t try to DIY such an important fix. Call in the professionals from JES and let them complete the job instead.

Finding the Best Solutions for Your Crawl Space Problems

Different crawl space problems require different solutions. For example, an expert may recommend replacing crawl space vents with something else that can more effectively keep your crawl space healthy, but that’s not a one-size-fits-all solution.

Instead, it’s important that you get your suggestions straight from the expert. Don’t try to look around on the internet and see whether someone’s given an answer to your problem. You can’t DIY a foundation repair. It’s just too risky.

Reduce your risk and repair your problems with a free foundation inspection from JES. It’s the best way to make sure you know exactly what’s going on under your home.

The Benefits of Fixing It Now

Even if you’re fully convinced of the need to fix your foundation vents with an expert, you still might not know why you need to fix it as soon as possible. Can’t you just put it off until it actually starts causing problems?

That’s not a great position to take, especially not when the health of your entire home could be at stake. If you choose to fix it now, you can take advantage of all these benefits.


Learn why you need to address crawl space moisture and humidity today.

Moisture in your crawl space can significantly impact your family’s quality of life in a number of ways. First, it can just make the home feel uncomfortable. The mugginess of the air isn’t fun to be around even if it’s relatively cool air.

However, potentially even more important is the fact that moisture in the air can lead to serious health problems. Plus, if there’s mold anywhere in your home, your family can breathe in those mold spores, leading to even more health issues.

When you trust a JES foundation repair expert to help you fix your foundation, you’re improving the quality of life for everyone who lives in your home. 

The earlier you catch a problem, the more likely you are to avoid extremely severe damage because of that problem. After all, the most severe damage needs a long time to develop.

If you catch your crawl space moisture problem early, it doesn’t give time for mold, mildew and wood rot to develop. In turn, that doesn’t give time for bugs and rodents to show up, and it doesn’t give time for your home’s foundation to suffer irreparable damage.

Essentially, the earlier you call a professional, the better. With the availability of a free inspection from JES, you have nothing to lose and everything to gain. 

If you’ve never had a formal inspection of your crawl space and foundation, you probably don’t really know what’s going on down there. What if you’re dealing with other problems you don’t even know about yet?

Have you noticed nail pops in your walls? Do your floors seem strangely uneven? Does it feel like one of your walls is leaning in on itself? These are all potential signs that there’s something wrong with your foundation. You need to fix foundation problems as early as possible. That’s exactly what a foundation inspection can do.

The best way to make sure your foundation is safe and healthy is to schedule a free inspection with JES. With your free inspection, you’ll either learn that everything’s okay, or you’ll get a full report on what you can do to make it okay.

We now have a crawl space to be proud of and feel very secure that we will not have any future problems. Pauline and I will not hesitate in recommending your company to anybody. We thank you for your services.

~ Burt and Pauline S., Williamsburg, VA

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