Optigrün Pitched Roof Board FKD 58SD is used for pitched roofs with a pitch in between 15° and 30°. Made from expanded polystyrene. With precisely fitting Z-fold on top and bottom edge and lateral indentations for safe shear stress transfer in direction of the water flow; no possibility of substrate reaching the protective layer thanks to tight fit of horizontal and lateral edges. The integrated chambers provide excellent anti-slippage for the substrate, high water storage capacity and an integrated water distribution system. Lay out according to manufacturer informations with max. 80 mm overfill (incl. vegetation mat).