Vapor barriers are essential for preventing soil moisture from seeping into the crawl space. However, using the proper liner thickness is crucial for adequately protecting the area from damaging elements.
This page outlines the differences between 10-mil vs. 15-mil vapor barrier liners for crawl space encapsulation so you can make an informed decision for your home.
When researching which vapor barrier thickness is best for your home, you may feel overwhelmed by the options. While 10-mil and 15-mil are common liner thicknesses, there may be better choices. Both offer some protection, but the comparison between 10-mil and 15-mil is notably different. You must understand each liner thickness to determine which is best suited for your home. Here’s what you need to know:
Vapor barrier thickness is measured in mils, and one mil equals one-thousandth of an inch. This minute unit of measurement makes it easier to understand why even minor thickness discrepancies significantly impact performance.
Here are the common crawl space vapor barrier thicknesses:
The thinnest crawl space vapor barrier is 6-mil thick. Many individuals choose 6-mil vapor barrier installation for cost reasons. However, the attempt to save money actually costs more in the long term.
Previously, building codes allowed for using 6-mil vapor barriers to meet the minimum requirements for crawl spaces. However, this liner does not meet today’s standards or provide optimal protection for these areas. A 6-mil vapor barrier is best suited for temporary moisture management or as a flooring underlayment.
A 6-mil vapor barrier is roughly twice as thick as a standard plastic grocery bag. Would you want to protect your crawl space against moisture using two grocery bags? Probably not. This illustration explains why a 6-mil vapor barrier might not be the best choice for long-term moisture management.
A 10-mil barrier is less common than a six or 12-mil barrier. This barrier addresses some problems experienced with a thinner 6-mil barrier version; however, the additional 4-mil doesn’t provide much coverage because of the minute measurement.
Many postcards are printed on paper that measures around 10-mil. A vapor barrier with this thickness isn’t adequate to prevent tearing and other damage over time.
12-mil vapor barriers have been the industry standard for some time. They are twice as thick as the fragile 6-mil barrier and are an affordable, more durable option.
Although 12-mil can be an effective option for some crawl spaces, it’s not the most durable option. They can be challenging to properly secure to crawl space walls, risking gaps and overlaps where moisture can seep through.
In recent years, there has been a growing trend toward even thicker vapor barriers, like 20-mil, for superior crawl space moisture protection.
15-mil vapor barriers are slightly thicker and more durable than 6-mil, 10-mil, and 12-mil liners. However, they are not comparable to the heavier, more robust 20-mil vapor barrier.
Most of your home’s indoor air originates from the crawl space. While 15-mil is an improvement over thinner vapor barrier options, 20-mil liners typically provide superior protection.
When choosing a vapor barrier thickness, considering other factors like local climate, soil conditions, and the overall condition of the crawl space is crucial.
A 20-mil crawl space vapor barrier is the most durable home-use option. It is the best vapor barrier for crawl spaces because it fully protects against moisture. 20-mil liners are less likely to tear or puncture in less-than-ideal crawl space environments.
JES Foundation Repair installs the 20-mil CrawlSeal liner, a robust 7-ply polyethylene vapor barrier offering high performance and low maintenance. Our liner prevents moisture and vapor intrusion and contains UV protection and antimicrobial properties to prevent mold growth and mildew.
CrawlSeal’s 20-mil thickness withstands heavier traffic, making crawl space storage and accessibility possible. Due to its efficiency, a 20-mil vapor barrier also reduces high energy bills. Reliable 20-mil vapor barriers are superior for crawl space moisture and home protection.
Tearing and punctures are the most common problems with thin crawl space vapor barriers. Thin barriers are also prone to erosion from the moisture they encounter while performing their job.
Optimal moisture protection is provided by a high-quality crawl space vapor barrier product and professional installation. Inexpensive, thinner versions are a temporary fix for a long-term issue.
Building codes maintain safety and are frequently updated with additional protocols because even minor errors can lead to an unstable and potentially dangerous structure.
Thinner crawl space vapor barriers do not meet most building code requirements. While building codes are less likely to be enforced in residential homes, compliance is crucial for safety and structural integrity. Check your area’s local regulations for specific requirements.
Exceeding requirements with a 20-mil vapor barrier provides peace of mind and increased safety.
Overall, a thin crawl space vapor barrier will not perform as effectively as a thicker one. If the barrier suffers even the slightest puncture, you risk pest infestations, moisture, and humidity.
Choosing a high-performance crawl space vapor barrier prevents these damages and provides optimal protection. JES experts recommend the 20-mil CrawlSeal vapor barrier for superior results.
Vapor barriers are a crucial component in the encapsulation process. Crawl space encapsulation involves installing waterproofing measures to block moisture seepage in a dirt-floor crawl space. Vapor barriers play a significant role in ensuring your crawl space remains dry.
A high-quality, 20-mil crawl space vapor barrier provides the following benefits:
If you discover moisture in the crawl space after encapsulation, it indicates a problem—either the encapsulation is incomplete, or water is entering from another source.
A crawl space vapor barrier allows moisture to collect on its surface, making moisture much easier to identify during inspections. JES experts identify crawl space moisture, humidity, condensation, and standing water during a free initial inspection.
Crawl space vapor barriers are definitely not a DIY project. Some home repairs are doable on your own, which leads many homeowners to ask whether they can DIY more substantial repairs and installations.
If you need crawl space vapor barrier installation, trust a professional like JES Foundation Repair.
Professional crawl space encapsulation ensures the work is done right the first time, preventing moisture issues from improper encapsulation. Hiring a professional offers the following benefits:
Crawl space encapsulation with a vapor barrier creates a moisture-free environment, reducing mold, wood rot, structural damage, uneven floors, and more.
JES Foundation Repair experts provide a free inspection to identify problems and address crawl space moisture at its source for long-term relief. We also implement dehumidifiers, sump pump systems, and interior drainage solutions to ensure complete encapsulation.
Want to learn more about crawl space vapor barriers or encapsulation? Contact JES Foundation Repair for a free inspection and no-obligation estimate. We identify moisture sources and create customized repair plans suited to your home’s needs. Proudly serving Virginia, DC, Maryland, and North Carolina, discover the difference a durable vapor barrier can make in your home.
Your crawl space needs a 20-mil vapor barrier to get the maximum benefits of a crawl space vapor barrier. If you want the benefits from a CrawlSeal™ 20–mil crawl space vapor barrier, you should schedule an inspection with a JES expert to discuss your options.
In some cases, you might see someone claiming that a cheaper 12–mil vapor barrier is fine for your crawl space. The comparison between the 12–mil vs. 20–mil vapor barrier goes much deeper than just the cost, however. If you choose the higher-quality 20–mil vapor barrier for your crawl space, you’ll be more thoroughly protected from moisture.
When you put in a 20-mil crawl space vapor barrier, you’re going to use a thick plastic barrier. This plastic barrier helps you keep the water vapor barrier on one side. That’s why a true crawl space repair expert will recommend a thick, strong 20–mil vapor barrier for your crawl space.
Groundworks Editorial Team
