One of the most common questions we get, what type of crawl space vapor barrier size do I need for my crawl space?

Selecting the tight vapor barrier is important, so we want to walk you through all the different crawl space vapor barrier sizes that are available to you.

Once you know what vapor barrier thickness you need, then we’ll discuss which crawl space vapor barriers are the best on the market (with data to back it)

What Crawl Space Vapor Barrier Thickness Do I Need?

The thickness of the vapor barrier is going to depend on your current crawl space and your crawl space environment.

There’s a few different vapor barrier sizes you could use;

  • 6 Mil Crawl Space Vapor Barrier
  • 8 Mil Crawl Space Vapor Barrier
  • 10 Mil Crawl Space Vapor Barrier
  • 12 Mil Crawl Space Vapor Barrier
  • 20 Mil Crawl Space Vapor Barrier

To help you understand which crawl space liner you’re going to need, we’ll discuss each one at a time and what each one is used for.

6 Mil Crawl Space Vapor Barrier

The 6 mil vapor barrier is used in small crawl spaces. This is a thin crawl space liner. With the 6 mil, you can’t store items on top of the vapor barrier nor should you walk on it. If you do, it should be the least possible.

A 6 mil liner is common in smaller areas.

8 Mil Crawl Space Vapor Barrier

The 8 mil vapor barrier is used in small to medium sized crawl spaces. This is a smaller crawl space liner. With the 8 mil, you don’t want to store many items on top of the vapor barrier nor walk over the vapor barrier a lot. If you do, it should be the least possible.

10 Mil Crawl Space Vapor Barrier

The 10 mil vapor barrier is used in small to medium sized crawl spaces. This is a mid-sized crawl space liner. With the 10 mil, you can store items on top of the vapor barrier and you can walk across it. With that in mind, you should only store a few items on top. Walking on this liner is ok but no heavy foot traffic.

12 Mil Crawl Space Vapor Barrier

The 12 mil vapor barrier is used in mid-sized crawl spaces and bigger. This is a mid tier crawl space liner. With the 12 mil, you can store items on top of the vapor barrier and you can walk across it. With the right 12 mil liner, you can store a fair amount of items on top and foot traffic won’t hurt it.

The 12 mil is commonly used on the crawl space walls.

20 Mil Crawl Space Vapor Barrier

The 20 mil vapor barrier is used in mid-sized crawl spaces and bigger. This is a mid tier crawl space liner. With the 20 mil, you can store items on top of the vapor barrier and you can walk across it. With the right 20 mil liner, you can store a fair amount of items on top and foot traffic won’t hurt it.

The 20 mil is commonly used on the crawl space floors.