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crawl space encapsulation

Conditioning Your Crawl Space: Sealing Vents and Other Air Leaks

Learn more about how conditioning and sealing your crawl space will benefit your home.

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An important step in the crawl space encapsulation process is sealing vents and making sure other outside air doesn’t come inside. This typically comes after installing interior drainage, a sump pump system, and then a vapor barrier liner and dehumidifier. Sealing vents and avoiding other air leaks is an important part of crawl space encapsulation, but it’s one you might not know a lot about. Why do you need to seal your crawl space vents?

encapsulated crawl space

Many homeowners, in fact, don’t know a lot about crawl space encapsulation, including the issue of sealing crawl space vents and avoiding leaks of outside air. Many of them believe these crawl space vents genuinely help their home. If there’s such a big belief that crawl space venting helps, why do you need to seal your crawl space vents?


Why Open Crawl Spaces are Bad

The biggest problem is that so-called “experts” have often told people that vents actually benefit their crawl space, so learning that it’s not the case can be devastating. Open crawl space vents, especially those that are open year-round, can cause a huge variety of problems.


By far the largest problem associated with open crawl space vents is moisture. The prevailing wisdom for many years had been that by letting the crawl space “breathe,” it was less likely that there would be a buildup of moisture. In fact, this was such a widely believed concept that for many years, it was a requirement in building codes.

The problem is that with open crawl space vents, warm and cool air meet, changing the condensation point of the air and unintentionally causing water buildup in the home. With open crawl space vents, you’re actually more likely to end up with added moisture. This moisture will just start to condense on the inside of the home.

Moisture leads to all sorts of terrible things in your home. For example, if you’re dealing with crawl space moisture, chances are that you’ll also end up with mold, mildew, and sometimes even wood rot. Plus, standing water in your crawl space can lead to material degradation and sometimes electrical hazards, which aren’t something you want to deal with.

Wood Rot

Another significant problem in homes with open crawl space vents is wood rot. That’s because wood rot grows most commonly in homes with a lot of moisture and a medium temperature, which typically describes most homes with open crawl space vents. Wood rot flourishes in many homes that have open crawl space vents.

Wood rot can be a giant problem. In fact, if you let it grow for too long, wood rot can cause irreparable damages. You may have to replace entire sections of your home structure, even sections that don’t seem to have damage on the surface. Wood rot can grow through wood pieces that don’t seem to have this type of rot, and that can mean huge financial problems.

True wood rot is a scourge rivaled possibly only by termites, and it’s something you want to stay away from as thoroughly as possible. If you can avoid wood rot simply by closing your crawl spaces, why wouldn’t you want to take that one step? It’s a simple step that can help your crawl space stay much healthier.

Mold and Mildew

By far the most common issue that most homeowners associate with water is mold and mildew. Both of these problems require an extremely high level of moisture in the air before they can appear, but resting condensation can also cause a high enough level of moisture. Whether you have high relative humidity or just condensation on the walls, mold and mildew can start to form.

If you have a moderately warm home and a lot of moisture, you’re almost certainly going to end up with mold and mildew to some extent. This can exacerbate allergies, weaken your home structure, and cause a musty smell. All of these are terrible things to have to deal with in your home and closing your crawl space vents can avoid them.

Some homeowners who have never had an encapsulated crawl space just feel like this is how it has to be. In these cases, it’s common for homeowners to feel like there’s no option except to leave the crawl space as-is and deal with the mold and mildew. However, that actually couldn’t be further from the truth. If you encapsulate your crawl space, you can almost always get rid of these concerns.

The good news is that if you’re willing to condition your crawl space, you can reap the benefits. These are a few of those benefits.

Reduced Allergy Flareups

A small but significant benefit of a conditioned crawl space is that you’re less likely to have allergy flareups. Dust mites, mold, mildew, and other moisture-related issues can trigger allergies, which means it’s common for allergy sufferers to have a hard time in moist homes. You might not even realize that this is what’s causing your allergy flareups.

When you take steps to avoid moisture in a home’s crawl space, you can also reduce allergies for yourself and people in your family. This benefit alone can be worth it for many allergy sufferers, as mold and dust mite allergies can feel unbearable. Some allergy sufferers don’t even realize they’ve been having allergies until those allergies are gone.

Even if you don’t have serious allergies, it’s not fun for anyone to have coughing or sneezing fits, no matter how infrequently they occur. Wouldn’t you rather reduce the amount of coughing and sneezing you have to deal with, even if the amount you’re dealing with is already relatively low?

Energy Savings

Perhaps the largest benefit of conditioning your crawl space is the energy savings. Advanced Energy has performed research to suggest homeowners may expect 15%-20% energy savings with an encapsulated crawl space versus an unencapsulated crawl space. It might not seem like much at first, but this is actually a huge amount.

When you do the math, you’ll realize that this can add up to huge savings over the time you live in your home. For many families, an unsealed and vented crawl space is wasting the monetary equivalent of up to 20 full tanks of gas every year. That’s enough savings to potentially offset the cost of encapsulating your crawl space.

Crawl spaces contribute to excess heating and cooling bills year-round because the outside temperature more easily comes into your home. That’s not the only way it impacts your bills, however. It also increases the relative moisture in your crawl space. High-moisture air is much more difficult to condition, which means you’ll probably turn the thermostat up and end up with a higher energy bill.

Sealing your crawl space vents is just one part of the encapsulation process. There are actually many steps in the encapsulation process because it can be difficult to complete encapsulation fully. Here’s an overview of that full process.

Address Standing Water and Leakage

First off, you need to address any standing water or other leakage you might be experiencing in the crawl space. For example, some people have puddles of water that come from previous water leaks, condensation, or faulty water drainage in your existing crawl space system. You have to address these problems first.

There is a number of ways to address standing water. If standing water is a regular problem, like if the home’s build causes water to accumulate in the crawl space on a regular basis, you may need to install a crawl space sump pump. However, in other cases, you might just need to vacuum the water out, because you won’t have recurring issues with crawl space water. It all has to do with the overarching problems, which a JES expert can help you uncover.

Install a Vapor Barrier Liner

The next step is to make sure you’re considering how water can come in from the ground. If you have a dirt crawl space, it’s important to realize that you’re never going to be able to have a fully dry crawl space unless you install a heavy-duty vapor barrier liner. Dirt without something over it will always have a direct connection to the water table, so water vapor will move up through this dirt, even if it looks totally dry on the surface.

There are ways to avoid this moisture issue, however. JES uses a 20-mil CrawlSeal vapor barrier to seal your crawl space dirt off from the moisture that wants to come up through it. CrawlSeal is well-manufactured and highly trusted, making it a great option for anyone who needs encapsulation for their crawl space. This is a great solution even if someone may need to inspect your crawl space in the future because it’s so thick.

Seal Exterior Openings

This is the current step: sealing the crawl space vents. Of course, crawl space vents aren’t the only exterior openings. You may have a loose crawl space door or even issues with other exterior openings.
Some crawl spaces have an entrance to the outside, often by means of a below-ground crawl space entrance. All of these entrances can be a breeding ground for pests and an easy place for moisture to enter if you’re not careful.

Closing your crawl space vents is an important part of sealing all exterior openings, but it’s obviously not the only thing you should be thinking about. You might need to replace your crawl space doors, install additional crawl space barriers, or otherwise seal various openings that allow your crawl space to have access to all types of moisture.

Add a Crawl Space Dehumidifier

In many cases, it’s a good idea to add a dehumidifier to your crawl space. Not all crawl spaces will need a dehumidifier, but it’s a great way to know exactly what the humidity level of your crawl space happens to be. That way, you can adjust or change things if you need to move anything around, and you never have to worry whether you’re maintaining a healthy level of humidity in your crawl space. The dehumidifier will do that automatically.

If you’re worried about whether or not your energy bill will go up dramatically due to your crawl space dehumidifier, rest assured that JES uses an energy-efficient crawl space dehumidifier that will provide as much dehumidification as possible while still only using a very small amount of energy. Plus, when you remove this significant source of humidity, as previously mentioned, you may actually find that your energy bill will get lower.

Contact a JES Expert to Learn More About Your Options

A closed crawl space should be something you pursue diligently. Instead of just allowing your crawl space to remain open, why not take the necessary steps to close it? Closed crawl spaces have a huge variety of benefits over open crawl spaces, and it can be beneficial for you to make the move toward a closed crawl space instead of an open crawl space.

These benefits come in a variety of shapes and sizes. You’ll likely have a lower heating and cooling bill, you’ll probably end up with fewer flare-ups for your allergies, and you’re much less likely to end up with an infestation of something like wood rot. These are all great reasons for you to pursue crawl space encapsulation.

Closing your crawl space doesn’t have to be difficult; many homeowners are able to pursue crawl space encapsulation much more easily than they ever thought possible. With the help of a JES expert, you may be able to reduce your crawl space costs and risks. You should request a free inspection to learn more about your potential options for crawl space encapsulation and conditioning with JES.

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