Rigid Foam Insulation Vapor Barrier

Keep foam board insulation away from direct sunlight prior to installation.

Rigid foam insulation vapor barrier.

They keep your home at a comfortable temperature without the need to crank your heat. However if your home is newer and it has xps or some other form of external vapor barrier on the outside of your foundation then using xps inside is not advisable because you can be creating double vapor barriers in this situation using a more permeable eps foam or rigid mineral wool panels like roxul comfortboard against the concrete is. To complete the vapor barrier you would want to foam seal or tape all the sides where the rigid meets timber because these gaps will facilitate vapor flow. This diagram shows how to install them in your crawl space.

When installing the foam use caulk or tape for maximum insulation between the material and the board or floor. Rigid insulation is one of the best tools to reduce your energy costs. All foam boards absorb water vapor. Dealing with the edges the foam insulation and two layers of plywood can add as much as 2 inches of height to the garage floor.

If you want to learn more about crawl space insulation check out this article. Technical information this product is combustible. Extruded polystyrene xps rigid foam insulation provides a weather resistant barrier when joints are sealed to enhance the building resistance to air and moisture penetration. However an installation between the studs can pose a challenge.

You can even place it under the foundation slab. It will degrade its r value. But when adding insulation to an existing slab the vapor barrier is laid over the top of the slab before the foam insulating panels are installed. By installing the crawl space vapor barrier over the insulation you will prevent holes in the vapor barrier from securing the rigid foam to.

A protective barrier or thermal barrier is required as specifi ed in the appropriate building code. However an installation between the studs can pose a challenge. Cover the insulation with a vapor barrier before you install it. Avoidance of the installation of vapor barriers such as polyethylene vapor barriers foil faced batt insulation and reflective radiant barrier foil insulation on the interior of air conditioned assemblies a practice that has been linked with moldy buildings lstiburek 2002.

Rigid foam insulation is usually a qualified vapor barrier. Rigid foam insulation packs a lot of r value into a thin package but not all rigid foam performs the same. Choose rigid insulation wisely and consider the effect its characteristics will have on the performance of the your project overall product cost and the best way to get the bang for your buck.