... extruded plastic foamed heat insulation board, which is extruded by polystyrene colophony, is the exclusive use for make geothermic floor, ... fastly.2. Low thermal conductivity coefficient: only 0.028. This is the best coefficient in heat insulation building materials. The heat ... into the patterns, and they are flat and regular. It is save time, labourers, materials, especially, save many aluminum foils ...