Quik Therm SGI (Subgrade Insulation) is a rugged yet flexible expanded polystyrene that is used under concrete slabs. With its layers of advanced reflective polymer facers it provides a vapour and radon barrier. These reflective facers have a top clear layer so it will not react with the concrete. There is no need to use poly with this product. It is available in convenient 4′ x 8′ sheets and can easily be walked on during installation without the fear of it cracking or breaking. This insulation is manufactured in Canada. It is a complete air, vapour, radon and radiant barrier designed for below grade applications such as exterior concrete walls or below concrete floors. This superior insulation is a closed-cell, lightweight, expanded polystyrene and hermetically sealed with an advanced metallic polymer facer on each side. It is rugged and durable, will not crack, chip or break, can be walked on during installation without compromising the product and has no thermal drift. It’s R-value will remain stable.