Do I Need a 20-mil Crawl Space Moisture Barrier?

A 20-mil crawl space moisture barrier is recommended by Foundation Recovery Systems. It’s much thicker than the required minimum and even thicker than many contractors will recommend. Is it really important that you get a 20-mil barrier? 

• Thinner Vapor Barriers Are Less Effective 

A 6-mil crawl space moisture barrier is typically the minimum requirement. However, this is the absolute minimum requirement, so it’s not the best option for your crawl space. This barrier thickness is well known for being easy to tear and not very effective, so it’s not a good choice unless your main concern is cost. 

A 10- or 12-mil crawl space moisture barrier, by contrast, will be much more effective than a 6-mil crawl space moisture barrier, as it’s about twice as thick. However, Foundation Recovery Systems doesn’t recommend this barrier because it’s still not as effective as it should be. All thinner vapor barriers are more prone to rips, tears, punctures, and general wear-and-tear. 

• 20-mil Barriers Offer Better Benefits 

If you want a firm boundary that keeps your crawl space safe, a 20-mil barrier is your best option. With a 20-mil barrier, you don’t have to worry about whether you’ll break it when you use your crawl space. A 20-mil barrier is better and more effective than the 10- or 12-mil barrier and far superior to the 6-mil options. 

A 20-mil vapor barrier is the most commonly recommended by professionals because of its superior tear and puncture resistance. You will not have to worry about the vapor barrier tearing when you move over it. Likewise, this vapor barrier tends to be more resistant to mold and pest incursion, thereby providing a more complete and lasting level of protection.