They are drainage boards made of high-density expande polystyrene, used as a soil retainer in garden roof areas with a slope of up to 35 degrees. A special lightened soil mixture is placed directly into it.
They are drainage boards made of high-density expande polystyrene, used as a soil retainer in garden roof areas with a slope of up to 35 degrees. A special lightened soil mixture is placed directly into it.