Surface joints must be placed within the tiled surface regardless of substrate conditions. They provide stress relief from movements in the tile field due to thermal and moisture expansion/contraction and loading. Schluter-DILEX-BWB is a prefabricated, maintenance-free surface movement joint profile. It features trapezoid-perforated anchoring legs, made of recycled rigid PVC, which are secured in the mortar bond coat and provide edge protection for adjacent tiles. The profile separates individual fields in the tile covering and accommodates movement via the soft chlorinated polyethylene (CPE) movement zone, which also forms the visible surface. The movement zone is 3/8" (10 mm) wide, matching common movement joint widths, and is thus capable of accommodating relatively large movements. Dilex-BWB is sold per 8' piece. Height and color selection is needed for this item.