The Stile Board System includes single slope extender panels made of extruded polystyrene (XPS). These panels are integrated with a continuous 1:80 fall gradient, designed to extend the slope to reach longer spans up to 3600mm. The extender panels maintain consistent panel thick-nesses of 36mm, 51mm, and 66mm, ensuring seamless inte-gration with the main panels and providing efficient water drainage across extended distances.