Smart Slab is the first concrete slab fabricated with a 3D-printed formwork. 3D printing overcomes the geometric limitations of traditional formwork fabrication methods. Furthermore, it enables the construction of integrative concrete elements with elaborate, free-form and highly detailed surfaces and smart construction details. 3D printing has the added benefit that geometric complexity and differentiation come at no additional production cost.

The 78-square-meter Smart Slab that is fabricated for the DFAB House, cantilevers over the S-shaped Mesh Mould wall and carries the two-story timber unit above it. The Smart Slab comprises eleven 7.4-meter-long segments which are prefabricated and then mechanically joined using post-tensioning cables.

The geometry of the Smart Slab is structurally optimized for its challenging load-case, involving cantilevers of up to 4.5 meters. The material is distributed in a hierarchical grid of curved ribs, which vary between 30 and 60 centimeters in depth. The 1.5 cm thick concrete fields between these ribs are domed to maximize stability and to minimize the amount of material needed. Consequently the slab only weighs 15 tonnes, almost 70% less in comparison to a conventional solid concrete slab.