Misconception: Vapor Barrier Will Insulate Crawl Space
Many crawl space contractors tell homeowners the vapor barrier will insulate the crawl space. We have homeowners ask if this is true and the short of it is no.
Vapor barrier is designed to inhibit moisture, not insulate (unless it is InsulBarrier). There are some insulation vapor barriers on the market and we use a great one, but most contractors are calling the plastic itself an insulator.
What is Insulation Vapor Barrier
If you want to retard moisture and insulate your crawl space, say hello to Insul-Barrier. This is a unique product we can install for you. Insul-Barrier is also available for the DIYer on our DIY Store.
Insul-Barrier is an R-8 moisture barrier that can be increased to an R-12 with proper furring of the foundation wall to create an air gap. The air gap behind the Insul-Barrier is a great way to add more R-value with just a bead of spray foam.

Is Vapor Barrier an Insulator?
To the best of my knowledge, crawl space vapor barrier does not carry an R-value unless it is Insul-Barrier. The crawl space companies that push vapor barrier as an insulation material are really doing a disservice to the homeowner by allowing them to believe insulation is not needed. The Department of Energy states that in addition to a properly installed vapor barrier you should insulate either the sub-floor or foundation walls of your crawl space. The best way to describe vapor barrier is a retarder of moisture, but not a valid way to insulate the crawl space.



