Wedi board is a rigid, lightweight, waterproof substrate that cuts easily with a utility knife and is perfect for mosaics. The board has a solid Styrofoam brand foam core with a thin coat of polymer modified mortar over fiberglass mesh on each side, giving it the distinctive gray texture/color and blue edges. Wedi can be used on either floors or walls and is good in either interior or exterior installations. We carry it in both 1/4" and 1/2" thickness and sell it by the square foot. It is imperative when working with Wedi to consider how the piece will be hung PRIOR to the creation of the mosaic. So, whether you want to mount it permanently or hang it as a piece of artwork without a frame, planting Wedi Washers BEFORE you begin to mosaic is vital! We offer two hanging options. 1. A picture kit contains 4 Wedi Washers, 2 Screws, 2 Nuts, 2 D-Rings. 2. Individual Wedi Washers.