The Blog

5 Reasons Your Home Needs a Vapor Barrier

By Mike on April 19, 2016

An ordinary crawl space might house any number of systems, and they need just as much protection as you do.

What goes on inside your crawl space? It's not just a vacant, or mostly vacant, area underneath the house. Some houses have HVAC ductwork down there, and some have wiring and plumbing. Some have none of those things, but the framework of the house is still exposed.

Regardless of what's under your floor, it's susceptible to damage from the moisture that's in the soil. But with a vapor barrier, you've got a drier and happier home, even in the part where you don't live.

Here are just a few of the many reasons why a vapor barrier is a great idea:

#1: Keep Moisture in the Soil Where it Belongs

A vapor barrier keeps your home drier. That's what the EPA says, and it especially recommends it for older homes to control dampness. In a maritime climate such as what we've got around Seattle, moisture in the soil is a given. That's part of what makes this area of the country so glorious, but it's also a hazard to your home if it's left to its own devices.

This thin sheeting in the crawl space helps create a divide between water and your home. Spread uniformly across the soil and partway up onto the crawl space walls, it keeps water in the soil instead of in the crawl space.

#2: Protect Ductwork from Rust and Corrosion

Water and metal are never a good combination, unless you're going for that rustic look. If your home has ductwork running underneath, it's at risk of corrosion. If part of your HVAC system is installed under the house, you've got more to be concerned about.

Even galvanized, stainless and coated metal components aren't permanently safe from the damaging effects of moisture. In time, all of those protective measures can fail. And where there's a fastener, such as metal screws on ductwork, you've got a moisture point of entry. Install a barrier, and you'll help protect your systems investments. You'll also help regulate your home's temperature, which means less chance of a busted water supply line in winter.

#3: Guard Against Wiring Hazards

If there's anything worse than moisture and metal, it's moisture and metal plus electricity. Wiring that runs through the crawl space is protected, either by a conduit or by a plastic sheathing. But where there is a joint or connection, such as a junction box, you've got another point of entry for moisture.

Another hazard under the house is animals. All that it takes is one curious raccoon fiddling with a wire to rip the sheath or loosen up a conduit connector. If you have a vapor barrier, there's less chance of moisture infiltration before you detect the problem.


Vapor barriers vary, but they all help keep moisture in the soil from making its way up into your home.

#4: Maintain a Drier Home

Have you ever felt like your home is damp? Most homes get that way once in a while. But, in some, it's a chronic problem. Maybe your house smells musty, or perhaps you've got issues with mold and mildew. That can be an allergy trigger, and it's not healthy for anyone. The problem might not be inside, but underneath.

Moisture in the crawl space can be absorbed into surrounding materials. That means there's less chance of your foundation and framing members taking on water, and it also means your home will stay drier.

#5: Make Accessing the Crawl Space a Cleaner Job

Hardly anyone ranks heading into the crawl space as one of their favorite things to do. It's not exactly spacious, and some of them are downright shallow. If you have to access yours, chances are you'll spend some time on your hands and knees or maybe even your back or belly.

Now imagine how much nicer going into the crawl space would be with a dry surface between you and the damp soil under your house. That's what a vapor barrier can do. The thicker the barrier, the more likely it will be to stand up to crawling around. Unfortunatly vapor barriers can't make working in the crawl space more fun, but it can keep your clothes drier and probably cleaner. And without all of that exposed dirt, unwanted visitors are less likely to intrude.

For such an unassuming thing, a crawl space vapor barrier does a lot of work. It all leads back to keeping dampness in the soil and away from your home. At Clean Crawls, we've got years of experience cleaning and creating a drier and healthier environment under houses throughout Whatcom County.

If you're tired of that damp feeling or worried about corrosion, mold and mildew, we've got your home covered. Clean Crawls can handle all of your vapor barrier crawl space needs. Contact us today to learn more about how we can help your home stay healthier, drier and safer.

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