Does Spray Foam Insulation Require a Vapor Barrier?

Preventing the diffusion of moisture into your home is essential for avoiding mold growth and wood rot. As such, many people choose to install a vapor barrier. However, if you have spray foam insulation installed in your home, adding a vapor barrier may not be necessary. To learn about whether spray foam insulation requires a vapor barrier, continue reading.

What Is a Vapor Barrier?

In order to determine if your spray foam insulation will require the addition of a vapor barrier, it’s important to fully understand what a vapor barrier is. Essentially, a vapor barrier refers to a material that resists the diffusion of moisture. Typically, moisture barriers are made from a plastic or foil sheet and installed in various areas around a home, such as the floor, ceiling, wall, or roof. The main purpose of these barriers is to prevent water vapor from infiltrating an area where it could condense and cause mold growth or premature rotting.

Will You Need To Install a Vapor Barrier Over Spray Foam Insulation?

So, does spray foam insulation require a vapor barrier? It depends on what type of spray foam you use—open-cell or closed-cell spray foam. Open-cell spray foam insulation is not completely water-proof and will allow moisture to pass through it. As such, it will not form a sufficient vapor barrier, and you may need to have one installed depending on the location of the insulation and the climate of your area.

Closed-cell spray foam insulation, on the other hand, is completely moisture-resistant. Because it creates a moisture barrier on its own, there is no need to install a separate vapor barrier as long as a sufficient quantity of insulation has been implemented—typically around 1.5 inches thick. Thus, closed-cell spray foam insulation is often an ideal choice for locations that are typically more damp or humid, such as basements or crawl spaces.

Paragon Protection is a leading spray foam insulation contractor in Wauconda and the greater Chicago area. To have spray foam insulation installed in your home by a highly experienced company that you can trust, contact us today.