Vapor Barrier: How Does it Work and Does My Crawl Space Need One

Most of us don’t think about the space under our homes much.

But the truth is that you may end up needing costly repairs if you don’t stay on top of it.

Vapor barriers are a preventative measure for beneath our floors.

So, how do they work? Do you need one? Read on and we’ll help you make the decision for yourself.

What is a Vapor Barrier?

A vapor barrier is a thick plastic sheet that is laid throughout the crawlspace of the home. They come in a variety of thicknesses, but most people agree that 6 mil is the way to go.

The plastic keeps moisture from coming up underneath the ground and getting into the area underneath your home.

What Does a Vapor Barrier Prevent?

Moisture is the enemy of your home. It can cause tons of structural damage, mildew, and mold to appear no matter where the leak has been sprung if it’s not treated.

It’s doubly dangerous underneath your home. Most people don’t spend a lot of time in their crawl space after all and that means damage which could have been prevented goes unseen for lengthy periods of time.

The problems that can arise range from structural damage to health problems.

Structural damage often comes in the form of wet rot but there are other ways that moisture can begin to take things down. An unprotected crawlspace is a breeding ground for a variety of micro-organisms.

Oxidation processes, like rusting, can also occur in the metallic parts underneath your home. Over time it can eat through metals and create serious problems.

Mildew and mold will occur anywhere that moisture can get a decent hold. Even a raised humidity level is often enough to create a problem with these pesty microorganisms.

Do I Need a Vapor Barrier?

Some homes may not necessarily need a vapor barrier, but it’s easy to figure out if you do.

If the crawlspace underneath your home is dirt-floored then you should have one installed as soon as possible.

How Does Moisture Get in My Crawl Space?

There are a few different ways that you can end up with water in the crawlspace.

Leaks from above can cause problems, but those will generally be handled by a plumber. If that’s happened to an extensive degree you may need the area under your home serviced even if you have a vapor barrier.

Where vapor barriers really shine is preventing condensation and seepage.

Seepage occurs when the soil around your home gets wet and the water is carried under the home. It can make the soil moist or lead to water actually ending up in the crawl space itself depending on soil conditions.

A vapor barrier will prevent this rapid evaporation from causing problems.

The other big reason for moisture comes from condensation as air temperature changes. It’s less of a problem with lower humidity but water will almost always condense from the air as the local temperature changes.

How is the Barrier Installed?

Barrier installation can be done in a few easy steps by a trained professional.

First, the entire area beneath the home will need to be graded and any loose debris removed. Many companies will skip this step and it’s one of the biggest problems that an amateur may face.

You need a solid, flat base in order to install a vapor barrier in an ideal way. Without this, you’ll face clumping and other issues with the barrier that can cause serious problems.

The entire space will then need to be measured and any obstacles which may still remain have to be assessed. This is where the professional difference can really be seen. The average person doesn’t have the experience required to ensure a good layout with the poly sheeting used as a vapor barrier.

The sheet is then prepared, with cutouts made for obstacles.

Afterward, the plastic sheet needs to be laid down as tightly as possible and achieve close to 100% ground cover. Any exposed areas of dirt underneath the home have the potential to cause problems in the future.

Finally, the barrier is installed with stainless steel, corrosion-resistant staples and special buttons that prevent tearing.

All said and done it’s a large task that requires a lot of specialized knowledge, but most people will find it well worth the price of installation.

Do I Need to Do Any Maintenance?

For the most part, a vapor barrier will last for years to come.

Most people find that they can get away with just an annual inspection during the dry season. Just get under there with a flashlight and take a look around: if anything is torn then you should seek to get it repaired immediately.

When doing your inspection it’s also a good idea to check for any signs of rot or other damage in the subflooring and supports of your home. It’s just a safety measure and the barrier will prevent most problems but oddities do occur from time-to-time.

As long as you keep an eye on it here and there you’ll be fine.

Ready to Commit?

A vapor barrier isn’t that big of a commitment, but the damage it can prevent underneath your home is invaluable. If there’s a dirt floor underneath your crawl space you should handle the problem as soon as possible.

It’s not something that the average DIY-minded type should undertake. Every little detail counts and experience really matters.

If you think that you’re ready to get a new vapor barrier, then contact us and let’s see what we can do for your home!