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Crawl Space Vapor Barrier System

A crawl space vapor barrier is essential in creating a cleaner, brighter, and healthier crawl space. How can you make sure your crawl space is the best around?

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If there’s one thing that your crawl space may need, it’s a vapor barrier. Vapor barriers tend to be a requirement for any crawl space that has issues with moisture throughout it and the rest of the home. However, many homeowners don’t know how vastly important a crawl space vapor barrier can be to maintaining the health and structural integrity of a home. Here’s everything you need to know about a crawl space vapor barrier’s importance to your home.

Why Do You Need a Vapor Barrier System? 

Some homeowners aren’t quite sure why they need a crawl space vapor barrier in the first place. After all, if you’ve never had a crawl space vapor barrier before, you might not know why it’s important. Here are a few of the most important reasons for a crawl space vapor barrier in your home. 

  • Dirt Crawl Space 

If you have a dirt crawl space, you need a vapor barrier, no questions asked. Dirt crawl spaces tend to be the unhealthiest crawl spaces by far because they have no built-in waterproofing. They can become much less healthy, leading to recurring issues in the crawl space that you just can’t escape. 

A dirt crawl space is never going to be completely dry. Even if you dry out the top layer of the dirt, eventually moisture will rise through because it’s always retained somewhere deep in the ground. That’s why dirt crawl spaces need a crawl space vapor barrier, even if it doesn’t seem like they have much moisture in the ground. 

  • Water in Your Crawl Space 

What if you have standing water in your crawl space? Regardless of the other issues you may be having, standing water in your crawl space is an immense problem that you should address as soon as possible. Standing water heightens the humidity in the area and can waterlog organic materials, causing them to crumble and weaken. 

Most of the time, you’ll need a sump pump in your crawl space to remove standing water. If you find that you regularly have standing water issues in the crawl space, you might want to look into a sump pump that you can put in your crawl space at all times to pump the water out. Additionally, it’s important to combat whatever problem caused the water in the first place. 

  • High Indoor Humidity 

You may never have considered this concept, but high levels of indoor humidity in your home as a whole tend to indicate issues with your crawl space. The home shares up to 50% of its air with your crawl space. That means if you have high levels of humidity in the crawl space, you’re also going to end up with that humidity throughout the rest of the home. 

Unfortunately, many homeowners never consider this concept. They may try to deal with high indoor humidity issues by installing dehumidifiers throughout the home, never considering the base reason for the problem. Dehumidification will always work best if you do it at the source, which in this case is typically the crawl space. 

  • Issues with Crawl Space Insulation 

Crawl space insulation should be one of the most important things you maintain. If you don’t have great insulation, you’re essentially opening your home to all manner of weather issues. This is also the case if you have wet crawl space insulation or insulation that only passes the bare minimum of crawl space needs. 

Ideally, you should have a high-quality crawl space insulation process that maximizes your home’s crawl space health. If you have wet, damaged, or no crawl space insulation, you must consider replacing it. You’ll end up with a healthier crawl space and a healthier home overall. 

  • Pest Problems Throughout the Crawl Space 

Pests, including rodents, bugs, and other annoying infestations, can often come in through your crawl space. When you’re experiencing pest problems, you must trace those problems to their initial sources. For many homeowners, that initial source is the crawl space, which is why a vapor barrier can be a great tool to help in making your home less attractive to pests. These barriers and other solutions that help curb crawl space moisture can reduce pests’ interest in your space. 

Of course, there are many ways pests can come into your home, so it’s important to consider that a crawl space vapor barrier may not solve all your problems. That doesn’t mean you shouldn’t install a crawl space vapor barrier, however. With so many benefits to a crawl space vapor barrier, it’s a good idea for anyone. 

How to Choose the Right Crawl Space Vapor Barrier 

When it comes to choosing the right crawl space vapor barrier, there are two main concerns: thickness and the level of moisture permeation. Generally speaking, vapor barriers range from 6 mils in thickness to 20 mils, and theoretically, each of the options – 6-mil, 10-mil, 12-mil, and all the way to 20-mil – has its uses. Realistically, however, the thicker and less permeable a vapor barrier is, the more protection it will offer, and the less likely it is that you are going to have dampness, mold formation, and wear and tear. 

A 6-mil vapor barrier is only good for short-term use; it is fairly permeable and very likely to tear if you stand on or otherwise put any weight on it. As such, it is best for situations in which the crawl space is not likely to be entered at all or where cost is the overriding concern. A 12-mil vapor barrier is far more durable and will stand up to light or moderate activity in the short-term. If treated with antimicrobial agents, 12-mil barriers will also provide decent resistance to mold and mildew. 

By contrast, 20-mil crawl space liners are the toughest on the market. They will stand up to activity and the storage of goods in your crawl space and can be used on rocky or otherwise troublesome soil. As such, it is best to invest in 20-mil vapor barriers where possible as this will prevent you from having to continually replace them as a result of small tears and punctures. 

Vapor Barrier Systems


A dirt crawl space can be a huge problem for several reasons. Here are just a few of the reasons you might want to consider covering your dirt crawl space. 

  • Moisture from the Ground 

When you have a dirt crawl space, you’re always going to be fighting against moisture coming from the ground. It doesn’t matter how good you are at drying out the top layer of dirt; there’s always going to be moisture of some kind far underground. Of course, the actual level of dampness you need to deal with can vary depending on the soil under your home. 

Very moisture reactive soils, for example, like clay and peat, will become saturated during heavy rainfall or storms. This could lead to very severe dampness or even flooding inside your crawl space if you do not have drainage and moisture control measures in place. Installing a vapor barrier is one of the best things you can do to control moisture in your crawl space. 

  • Pests and Ants 

All sorts of pests can dig into the dirt and come up through a dirt crawl space. This is especially true when it comes to ants, as ants are incredible at digging up into wherever they’re trying to go. Of course, other pests like cockroaches and spiders can be attracted to a dirt crawl space because it is a perfect environment for some kinds of mold. 

If you want to give pests less reasons to be interested in you space, you need to make sure you’ve covered your dirt crawl space with a crawl space vapor barrier that works. Of course, they should also be paired with other moisture and dampness management solutions (for example a sump pump and dehumidifier). If you do not take additional steps to control moisture, you could end up trapping dampness in and exacerbating the issue.

If you are worried that you may have some problems within your property’s crawl space, there are a few signs that you can look out for. If you see any of these red flags, it is time to call in an expert to have your crawl space assessed. 

  • Excessive Humidity 

Humidity in a crawl space is somewhat inevitable unless you have invested in proper encapsulation and waterproofing. However, excessive humidity can lead to many problems beyond discomfort and dampness and can be a sign of deeper issues within the structure of your home (in particular your home’s foundation). 

If you notice that the walls of your crawl space are wet to the touch or there are droplets of water forming on the ceiling of the crawl space, the humidity level is far beyond normal and you should take steps to investigate the health of your property. You will likely find some structural damages if humidity has reached this level. 

  • Standing Water 

Standing water is a common problem in crawl spaces that have not been fully encapsulated, but there is a big difference between the standing water that commonly occurs after a heavy storm and persistent standing water with no discernible cause. If you have noticed that there are always pools of standing water in your crawl space, you likely have foundation damage. 

It is also likely that your property is on very expansive soil which, when saturated, is putting pressure onto the foundation, causing it to crack. When deep cracks form in your foundation, water will have a direct line into your property’s crawl space. This will lead to dampness and humidity in summer and standing water in the wettest seasons. 

  • Mold and Mildew 

Mold and mildew are pretty much a given in any crawl space which has issues with dampness and standing water, no matter the source of the moisture. If you notice pockets of mold and mildew spreading across the ceiling of your crawl space, or there is a musty smell as soon as you enter the crawl space, this is a problem sign. 

While mold and mildew seem fairly harmless, they can cause real trouble for your property and even your health. Certain species of mold can attract pests like mold mites and cockroaches while others can cause respiratory problems, skin irritation, and other health issues that range from uncomfortable to requiring medical intervention.

Crawl space moisture problems come from a variety of places, which means that a vapor barrier might not fix all your problems. Here’s what you need to know about moisture problems and crawl space vapor barriers. 

  • Moisture Problems in a Dirt Crawl Space 

A crawl space vapor barrier should help you avoid moisture problems from the dirt crawl space as long as you see that it is properly installed by a professional. If you’re able to seal the crawl space vapor barrier to the edges of the room, you can avoid most moisture problems that arise as a result of having dirt floors. 

This is because of how a durable, well-installed vapor barrier will prevent water from entering your crawl space in the first place. However, if you want to get the best possible results, you should also invest in drainage options like a perimeter drain and a sump pump. Also, installing a dehumidifier inside your crawl space will keep your crawl space healthy and dry. 

  • Moisture Problems from Flooding 

Flooding can come from either inside or outside the home. Either way, it’s important to make sure you’re putting safeguards into place to minimize the damage from flooding. That can include a crawl space vapor barrier, a sump pump, or crawl space vent covers. Ideally, you should invest in a mix of protective measures for your property. 

Even the best vapor barrier will only protect you from moisture that is seeping through your crawl space walls or floor. If the source of flooding is an unsealed vent or damage to your plumbing system, you will find that your vapor barrier does little other than trap the water in; in these cases, you will need different forms of protection for your home.

As you can see, adding a vapor barrier could be an incredibly useful way to maximize the health of your crawl space. However, you need to make sure you’ve installed it appropriately. Here’s what you can do to install your crawl space vapor barrier. 

  • DIY Installation 

A DIY installation is often very appealing to homeowners who love to do DIY projects or who think of themselves as handy. However, when it comes to a crawl space vapor barrier, DIY isn’t going to be your best option if you want a high-quality result. You need to make sure it’s applied appropriately for it to work, so you need an expert. 

If you try to install your vapor barrier alone you run the risk of damaging it during the process, which will cost you more money in the long run. Alternatively, you could install it improperly and leave a way in for water. This will not only cause the same issues as general dampness but will also exacerbate them as the moisture will be trapped. 

  • Expert Installation 

An expert installation will be your best bet when it comes to a crawl space vapor barrier. Instead of relying on your knowledge and experience, you can hand it over to an expert from Foundation Recovery Systems. That way, you can ensure you’re getting a great installation, a great product, and the best possible results for your home. 

Better still, you will find that this is an incredibly cost-effective way to have a vapor barrier installed because professional services come with the guarantee of a certain standard of work. If something goes wrong, you will be able to call the experts in to rectify it with no extra stress or pressure on you. Likewise, you can be sure that you are getting the best possible product for your money.

What Are the Steps to Installing a Crawl Space Vapor Barrier? 

Knowing a little bit more about your home’s crawl space vapor barrier can be a great way to understand why it’s so important. The steps of installing a crawl space vapor barrier can be confusing, but here’s what you need to know about the installation process. 

  • Install Airtight Doors and Crawl Space Vent Covers 

The first step to installing a crawl space vapor barrier has nothing to do with the barrier itself. Rather, it has to do with the rest of your crawl space. Loose crawl space doors and open crawl space vents can cause serious problems that are extremely difficult to fix overall. 

This is why you need to start with airtight crawl space doors and vent covers. The vapor barrier will only maintain a specific aspect of your crawl space. To see the true benefits of a crawl space vapor barrier, you’re going to want to utilize crawl space vent covers and airtight crawl space doors. 

  • Remove Standing Water in the Crawl Space 

Next up, if you have any standing water in the crawl space right now, you’re going to want to remove it. Standing water is one of the biggest problems your crawl space can have because it often spawns all sorts of other problems. You’re going to want to get rid of it before you install a crawl space vapor barrier. 

It’s not enough to install your crawl space vapor barrier on top of the standing water. If you have standing water underneath the crawl space vapor barrier, you’re going to still have problems with standing water, just underneath the barrier. Removing that water first and foremost is the best way to make sure your crawl space stays healthy in the long run. Protecting your crawl space with an interior drainage system and a sump pump is also crucial. 

  • Repair the Crawl Space Structure 

If there are any crawl space structural concerns that you’re having, this is the point where you may want to repair it. For example, some homes end up with wood rot throughout the crawl space. This is certainly an extremely frustrating problem to deal with, but it’s one you can fix if you remove the affected elements and replace them. 

This repair process will ensure that your crawl space structure stays high quality and beneficial toward your home while not providing any chance for the new structure to experience issues after you’ve added it. The repair process at this point is a great way to maintain your crawl space. 

  • Insulate the Crawl Space 

Next up, you must insulate the crawl space against the outside weather. This weather can come through in a variety of different ways. For example, your crawl space may end up being either warmer or colder than the weather in the rest of your home, which can artificially inflate your electricity bills and make it more difficult to have a healthy crawl space. 

The insulation process is an important element of having a healthy crawl space because it’s common for crawl space insulation to take a hit when you have an unhealthy space. This insulation process should be something that you pay close attention to. Ensure that you have enough insulation throughout your crawl space to keep it healthy. 

  • Encapsulate the Crawl Space with a Vapor Barrier 

This is the step you probably think about when you consider a crawl space vapor barrier. Although it’s not the only step to the crawl space vapor barrier process, it’s an extremely important element. With a crawl space vapor barrier, you’ll lay the barrier all across the crawl space, then typically seal it against the walls at least a few inches up to ensure it removes all entry for water vapor. 

You must have a crawl space vapor barrier that’s thick enough. The CrawlSeal™ system by Foundation Recovery Systems utilizes a 20-mil vapor barrier, which is almost three times the required minimum for most crawl space encapsulation building codes. 

  • Install a Dehumidifier 

Last, you may need to install a dehumidifier in the crawl space. A dehumidifier can help ensure that your crawl space stays at the right humidity level. There are many reasons a crawl space can have high levels of humidity, and the lack of a crawl space vapor barrier is just one. That’s exactly why a dehumidifier can be so beneficial. 

Of course, this is the last step in the process because you need all the previous steps to ensure that the dehumidifier works appropriately. If you don’t have a great crawl space vapor barrier, you’re going to end up with serious problems if you just try to install a dehumidifier. Add the crawl space vapor barrier first, then the dehumidifier next. 

Install an Effective Vapor Barrier with Help from Foundation Recovery Systems 

Crawl spaces need active maintenance. If you can maintain your crawl space to ensure it stays healthy, you’re going to end up with a happier home overall. However, many homeowners don’t maintain their crawl spaces, thus ensuring that these areas stay dingy, dusty, and unhealthy. The best way to combat this problem is to talk to a crawl space repair expert who can help you with your crawl space problems. The CrawlSeal™ vapor barrier system installed by Foundation Recovery Systems is one of the best ways you can attain this goal. Talk to a Foundation Recovery Systems expert today about whether CrawlSeal™ is right for your home and crawl space.

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