Beautiful Crawl Space Insulation. The walls are insulated with SilverGlo foam board insulation. Then TerraBlock foam insulation is installed across the floor and spiked down, which insulates and adds durability to the crawl space. Finally, a heavy-duty crawl space encapsulation liner is installed permanently across the floor and sealed to the walls and floor. Resulting in much lower humidity, much warmer floors upstairs, and fewer drafts