Does My Crawl Space Need a Vapor Barrier?
At first, you might think the flooring and insulation under your home are enough to keep your crawl space dry. Unfortunately, this is not the case. Let me put it bluntly, every crawl space should have a vapor barrier.
If someone asked me to select one moisture control system to install in the crawl space, the easy pick would be the vapor barrier. The materials needed are easily available at the local hardware store. If you are willing to work within the confines of the crawl space, the installation of the vapor barrier is simple. A weekend warrior can install one by himself in a few hours. The question is not if you need a vapor barrier for your crawl space. It should be about the type and thickness of liner and what degree of moisture control should be used to keep things dry and mold-free.
SO WHAT IS A VAPOR BARRIER, AND WHY DO I NEED ONE?
A vapor barrier is a plastic liner that covers the ground of your crawl space. Its purpose is to block moisture from the soil from getting into your crawl space.
From experience, the worst crawl space mold issues we see are the ones found with a missing vapor barrier.
Why you ask? The earth is an extremely damp place. The amount of water that transpires from the earth’s surface into the atmosphere is tremendous.
If your house does not have a vapor barrier in the crawl space, the moisture present in the ground surface rises up. Every inch of uncovered ground is another place where the transmission of moisture into the crawl space can happen. Sunlight and air movement are limited in the crawl space, unlike outside on a sunny, breezy day.
The relative humidity can be at 100% with visibly damp floor joist and other building materials. Little do you know, you have just created the perfect environment to grow mold.
Types of Vapor Barriers
The type of vapor barrier you choose will depend on how damp your crawl space is. It also depends on the ground type below the liner and your budget for the project.
Standard 6-mil and 10-mil Polyethylene Vapor Barrier
This standard vapor barrier is commonly installed by builders during home construction. Typically, 6-mil black plastic is used to cover the floor of the crawl space 100%. The seams are overlapped by 12 inches and secured to the ground using soil pins. This is the most basic type of vapor barrier. It is designed for light duty in crawl spaces with light to moderate moisture levels. Variations include taped seams to further reduce moisture in the crawl space. There is also a 10-mil vapor barrier upgrade for increased durability.
Reinforced Liners
The next upgrade would be a reinforced or woven crawl space liner.
Encapsulated Crawl Space
WHAT IF I FIND AN ISSUE IN MY CRAWL SPACE?
When you install or replace the vapor barrier in your crawl space, you will see an improvement in air quality. The air in your home should become less humid. Odors should dissipate, and you will have less dust in your home.
But if this doesn’t happen, or if you find signs of a developing problem, you will probably have more questions. Here are the most likely issues:
- Water in your crawl space: If you have more than just dampness in your crawl space, a vapor barrier may not be sufficient. It’s only meant to stop moisture, not water. If you have puddles of water under your home when it rains, you will need crawl space waterproofing. As rainwater collects in your crawl space, it will cause the vapor barrier to float around and render it ineffective.
- Dehumidifier Needed? If you install a vapor barrier, but the air still feels clammy, it may be time for a dehumidifier.
- If you find mold, please do not try to remove it yourself. For your safety, please have it evaluated by a professional first. We explain how mold removal and remediation is done. We provide pricing and describe options on this page.
DOES YOUR CRAWL SPACE NEED REPAIRS?
You will want to find an experienced local company and request a quote. Most contractors and waterproofing companies provide free estimates. Make sure they provide the quote in writing and clarify how long the pricing is valid.
If you live in Charlotte or the surrounding states, contact Fresh Air Companies. We specialize in waterproofing and provide free estimates. Our quotes are valid for a year after issue. We offer the best warranties in the business. We will schedule an appointment for you with one of our experienced project managers. They will evaluate your home and recommend the best course of action for you. This will help keep your home strong and healthy for years to come.
