Blu 60 Smooth slab is a contemporary modular slab with a refined smooth surface that enhances modern outdoor designs. Perfect for creating sleek patios, inviting walkways, and sophisticated pool decks, this slab is one of Techo-Bloc’s most iconic and versatile choices. Blu is available as a permeable pavement system in the 6x13 format. Its 9/32 in. joints are filled with clean open-graded stone rather than sand, yielding 4.8% open surface area (or 4.5% when the 6x13 is combined with other Blu sizes in a modular layout) and allowing surface water to infiltrate at up to 570 in./hr into an open-graded base, where it's stored and released to the subgrade. Permeable performance requires installation per Techo-Bloc's permeable pavement guide specification. All other Blu formats are non-permeable and require conventional surface drainage.