Is a Crawl Space Vapor Barrier Necessary?

Crawl Space Vapor Barrier Material

The vapor barrier material used by Crawl Space Ninja is proprietary and uniquely developed for the Ninja Crawl Space Encapsulation System. When we started encapsulating crawl spaces we used the same plastic as everyone else. We quickly realized the off-gassing of cat urine type odors is a real problem of some reinforced plastic materials.

How Thick Should Crawl Space Plastic Be?

Many contractors and manufacturers of crawl space vapor barrier material mislead people about the thickness of the plastic. We found plastic sold and installed as a reinforced 20-mil vapor barrier that was actually 6-mil. The thickness of the plastic was being measured at the reinforcement, not the plastic. Also, never use plastic as a substitute for crawl space insulation. Insulate and encapsulate your crawl space properly for maximum comfort and energy efficiency.

Crawl Space Ninja installs a thick mil solid-state or woven vapor barrier material. Our uniquely manufactured plastic will never separate and all surface area is a consistent thickness due to the Crawl Space Ninja Vapor Barrier being solid or woven and not thinly glued together sheets. Our vapor barrier is the maximum thickness it can be and still be flexible enough to install in crawl spaces. We have tested thicker plastic materials only to realize they would not bend as well as we needed them to.

Can Crawl Space Plastic Stop Radon?

Does a vapor barrier control radon levels? Not according to the information and situations we have found in the homes we have worked on in the past.

A crawl space vapor barrier is just that, VAPOR barrier. It is not an air barrier. Companies today are pushing vapor barriers as radon barriers and that simply is not true.

A vapor barrier is used in conjunction with a radon mitigation system. It is called sub-membrane depressurization. That does not make the plastic a radon barrier any more than concrete in a basement is a radon barrier.

Even if plastic was able to stop radon from entering the crawl space, it could still travel up cinder block walls or block pillars because cinder block does not stop radon either. Properly installing a sub-membrane radon mitigation system is the best practice for mitigating radon from your crawl space.

Should I Use an Underlayment?

Many crawl spaces have been used in the past as trash dumps so it is common to find debris like glass, cans, wood, roof shingles, siding, and even poured concrete. Some have gravel that can be very harsh to plastic.

Using an underlayment in the crawl space is a great way to protect your investment. An underlayment adds a layer of protection to the vapor barrier if you plan on storing items in the crawl space or if you have the need for plumbers, electricians, HVAC contractors, or other professionals to enter the space.

Utilizing a thick underlayment also gives the homeowner and contractor a bit of cushioning as they travel through the crawl space.

How Long Does a Vapor Barrier Last?

Watch Franchise owner, Michael Church, discuss the lifespan of vapor barriers in your crawl space. For more informational videos, check out our homeowner tips and guides on our YouTube Channel.

VIEW MORE VIDEOS ON VAPOR BARRIERS