Cap Ceilings Revisited: A Fabrication Future for a Material-Efficient Historic Ceiling System

Ceilings are key to more sustainable and climate-friendly construction. Slab systems comprise the most embodied carbon in proportion to all component groups. The shortage of materials after World War II brought a brief renaissance for vaulted masonry ceiling systems. The simplicity and effectiveness of the purely compression-loaded caps enabled rapid reconstruction with the available material and rubble. These characteristics require the system to be re-examined in light of today’s debates on resource scarcity and circularity. The research presents a LCA-Analysis, comparing six different ceiling systems under a uniform usage scenario. While a conventional concrete flat slab has a GWP of 136 kgCO2e/m2, the vaulted slab achieves a value of 64 kgCO2e/m2, representing a savings potential of 53%. Under the same conditions, masonry caps offer an operational solution that embodies less than half as much carbon as a conventional concrete ceiling. In addition, clear circularity properties can be demonstrated for the masonry cap ceilings. Circular economy principles are applied at both material and construction levels. The geometric precondition of cap ceilings with repetitive construction sequences lends itself to digital fabrication methods. This process enables further development of the historic form through multifunctional optimization. Hence, a 3D-printed acoustic brick was developed which enables the raw ceiling to meet a broad range of requirements. Our digital fabrication experiments show a unique combination in the joining of newly generated performative bricks and recycled material.