Integrating 3D-printed clay formwork into thin-vaulted green roof

Abstract

Green roofs (GRs) play an important role in urban sustainability initiatives, offering reduced building energy consumption and enhanced ecological performance through additional growing medium and vegetation layers. Nevertheless, these functional components introduce challenges such as extra structural load, greater slab thickness, and increased construction complexity. This research proposes a design-fabrication method for a thin-vaulted green roof prototype, featuring a compression-only surface and upstand ribs along unevenly distributed stress lines to achieve both lightweight properties and material efficiency compared to a conventional flat roof with GR systems. To realize such a non-standard and multifunctional structure, a hybrid formwork system combining 3D clay printed (3DCP) molds and a reusable, doubly curved foam base is proposed to handle geometric complexity and functional integration by incorporating stay-in-place formwork as the growing medium. An empirical construction experiment, conducted at a 1:5 scale, validates the proposed method with optimized fabrication procedures for a proposed application scenario in a community renovation project.