Foam glass gravel is a lightweight bulk aggregate made from recycled glass. It’s used across the construction industry as drainage and insulation in subslab insulation systems, and as lightweight fill for soft soil applications and green roof fill installations. At under 10 pounds per cubic foot, foam glass gravel is incredibly lightweight. The closed cell structure and high compressive strength make it highly versatile for design and construction. Glavel foam glass gravel is a Passive House High-performance building material.