The Dirt on Under-Slab Insulation

Insulating the perimeter of the foundation is important, and the insulation under the slab is just as important as the rest of the building to complete the thermal envelope.

Most basements are built in direct contact with ground. Concrete will absorb moisture, like a sponge, and the result is an uncomfortable, musty living space. The additional water introduced into the home can also lead to mold issues.

The basement floor is also a place of heat loss in the home. The idea that heat always rises isn't entirely true. Heat will flow toward relatively cooler places. If ground under the home is cooler than the basement temperature, which is the case in almost every climate year round, heat will naturally try to escape through the concrete slab.

Installing an insulation and vapor barrier between the concrete slab and the ground is the best practice in insulating basement floors. The insulation will help keep warm air in, and the vapor barrier will keep unwanted moisture out.

Plasti-Fab manufactures a variety of EPS product solutions to insulate below the slab: DuroFoam Insulation, PlastiSpan HD insulation, DuroSpan GPS insulation, as well as the higher compressive resistance lines of PlastiSpan 25, 30, 40 and even 60 psi.

Besides the comfort and moisture issues that insulating below the slab helps to alleviate, there is an additional health benefit to the home as well. Increased awareness of Radon gas and the need for mitigation systems has grown across the building market. Areas high in Radon gases are required to install these mitigation systems for the health of the home and the occupants. Plasti-Fab has worked hand in hand with Radon Environmental to develop Radon Guard Insulation, a key component in Radon mitigation systems. When insulating below the slab, using the Radon Guard insulation adds the health benefit to the insulation that is already working hard to add comfort to the living space.