The Chestnut Hypar Friedberg is a pioneering roof structure built from natural sweet chestnut wood (Castanea sativa), realized as a permanent demonstrator in Friedberg, Bavaria. With a 15-metre column-free span, it is currently the largest-span roof of its kind made entirely from this species. Its saddle-surface (hypar) geometry combines material efficiency with structural elegance, loading the joints primarily in compression and reducing the need for steel connectors. The structure is assembled from short individual wood elements using digital fabrication and CNC machining, making it well-suited for locally grown hardwoods that are typically limited in length and dimension. Sweet chestnut was chosen not only for its strength, but also for its resilience to warm and dry climates, making it a valuable species in climate-change-adapted forestry. The project is part of the BMEL/FNR-funded research initiative TSI, developed by the Digital Timber Construction group at TTZ Aichach.