Expol ThermaSlab S Grade is an expanded polystyrene used as thermal insulation for concrete slab floors. Known for its compressive strength, moisture resistance, and thermal protection, ThermaSlab is kiln dried to ensure that it will not shrink or sag and will last for the life of the building. It won't decay or rot, won’t support a fire and has no nutritional value to termites or rodents. ThermaSlab is also suitable for wall, retaining wall, cladding and skillion roof insulation.