HiRes: 3D-Printed Formwork for an Integrated Slab

Concrete floors produce significant carbon emissions during construction, operation, and decommissioning. Optimised designs featuring ribs and voids can minimise material use and integrate highly efficient heating, ventilation and air conditioning (HVAC) systems. However, such designs are rarely used in practice due to the fabrication challenges associated with complex shapes. Therefore, floor slabs are usually oversized, monolithic concrete boxes with standardised modular building services suspended below, concealed by a dropped ceiling. Dropped ceilings involve labour-intensive on-site works with significant embodied carbon, and HVAC systems are usually over-dimensioned to the nearest off-the-shelf size available. To address this ineffective practice, this paper presents a novel construction method that enables not only material reduction in floor slabs but also the integration of optimised building systems and aesthetic freedom. It aims to reduce the operational energy of concrete floors and increase user comfort through an HVAC concept that can be integrated into material-efficient slabs. The research is illustrated through a real-world project, the HiRes Slab, a 22 m2 floor slab for an office unit produced using a hybrid 3D-printed formwork system. The formwork is based on two 3D printing processes: polymer extrusion and binder jetting. Combining these different fabrication methods ensures a fast, resource-efficient process designed to be scalable and suitable for on-site applications. Computational optimisation and digital fabrication result in an energy-efficient floor with integrated building systems that reduce operational energy and improve comfort for occupants by reducing reaction times while retaining the benefits of thermal inertia.