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Ineffective Vapor Barrier

Some homeowners try to install vapor barriers on their own, and other professional contractors don’t use the best vapor barriers on the market. Either way, the crawl space continues to suffer.

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torn vapor barrier in crawl space

If you own a home with a crawl space foundation, you’ve likely heard of vapor barriers. You might have even installed one in the past, either on your own or with professional help. Vapor barriers need precise measurements and specialized tools for proper installation. Any error, even the smallest one, renders it ineffective. Let’s learn about the effects these vapor barriers have on your crawl space, and what causes them in the first place.

Does Your Vapor Barrier Look Like This?

Crawl space issues related to an ineffective vapor barrier are fairly common, especially in homes that tend to have older crawl spaces. JES can help you with your crawl space issues to fix them completely.

What Causes an Ineffective Vapor Barrier?

As mentioned, even the smallest errors during the installation process can cause a vapor barrier to fail. Here are some of the most common reasons they become ineffective.

  • Too Thin

Some vapor barriers are simply too thin to withstand the wear and tear they receive below your crawl space. Many hardware stores sell vapor barriers that are between 6-mil to 10-mil thick. For reference, a mil is equal to 0.001 inches. Installing a vapor barrier below 10-mil offers nearly zero protection for your crawl space. Even 10-mil is on the low end of professional-grade vapor barriers. Generally, vapor barriers should measure 20-mil to provide adequate protection. However, thickness isn’t the only thing that determines the effectiveness of a vapor barrier.

  • Poor Material

Most vapor barriers are made with polyethylene plastic, which provides fantastic protection if thick enough. However, many vapor barriers fail when they are not made with this material. Materials such as aluminum or stainless steel have been used for vapor barriers before. Sometimes, cheaper plastic is also used. These materials are not durable enough for use below your home and can easily become damaged by moisture in your crawl space. Plus, they can be easily ripped during installation, which ends up costing you more time and money.

  • Pests

If your vapor barrier is made with poor material and is not thick enough, it is especially prone to damage by pests. Animals are often drawn to your crawl space because it offers cover from storms or predators, and the humid air can be a warm place to breed, feed, or rest. When pests crawl along an ineffective vapor barrier, their claws or weight can tear through the material. Once holes are ripped into your vapor barrier, it is rendered useless and allows tons of moisture to infiltrate your crawl space anyway. Professionally installed vapor barriers from FSM are incredibly hard for critters to tear through, and usually discourages them from returning to your crawl space.



Yes, if installed correctly. Ineffective vapor barriers serve no purpose for homeowners and end up being a headache more than anything else. However, with a professionally installed vapor barrier, your crawl space becomes permanently protected. Investing in a vapor barrier ends up being worth it in this case, as it protects your crawl space from structural damage and actually saves you money. By keeping water vapor out of your crawl space, vapor barriers reduce the humidity inside your home and allow your HVAC system to work more efficiently. Anything that can save you utility bills is worth it in the long run.

Besides store-bought vapor barriers being too thin or made of poor materials, DIY installation has several other problems associated with it. Most important is your safety. Crawl spaces are tricky to traverse, and often filled with dirt and debris from the outside. For your personal safety, its best to hire a professional installer for a job like this that is used to working below homes and knows what to expect in a crawl space. Plus, one wrong move during a DIY project could damage important structures holding up your home. This ends up costing you even more money on repairs. Lastly, vapor barriers need to be installed perfectly to function. Some of the adhesive materials used to install vapor barriers are difficult to work with and could lead to a less than ideal result. 

Besides high moisture below your home, vapor barriers also prevent wood rot, mold, efflorescence, uneven floors, pests, standing water, and wet insulation from occurring in your crawl space. The craziest part is that’s not even everything a vapor barrier protects against. Since your home relies on your crawl space for solid support, installing a vapor barrier protects nearly everything in your home – including furniture, walls, and your loved ones.

Call Us for a Free Inspection

Since 2007, Foundation Systems of Michigan has been serving homeowners in Detroit, Grand Rapids, Kalamazoo, Toledo, and surrounding areas. We pride ourselves on an honest approach to business, and a dedication to exceptional work backed by experience. Accolades from the Better Business Bureau, Home Advisor, and Angi all prove our commitment to serving you. Contact us today to schedule a free inspection from one of our experienced technicians, and to take advantage of our crawl space encapsulation services!

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