ClayKnit: A composite structure of clay and knitted meshes

In this paper, we will demonstrate a new method of using knitted meshes to act as a formwork and to reinforce thin and hollow spatial clay structures. Currently, ceramic elements in the building industry are formed using extruding, pressing, or casting methods. This new approach can increase the usability of digitally fabricated lightweight elements, by spraying clay onto mass customised knitted meshes. Compared to fabrics that are used to shape concrete as a stay-in-place formwork, knitted meshes are available in various densities and changing patterns. They also offer the possibility to use a non-flexible thread as an elastic mesh. Knitted meshes are formed in a predefined shape by stretching them without the use of elaborate scaffolding. A specific liquid clay mixture is applied by spraying multiple layers onto the mesh by an industrial, six-axis robotic arm to precisely achieve variable wall thicknesses. Due to the complementary qualities of clay, which absorbs compressive forces and the threads, which absorb tensile forces, structures can be designed with a material optimisation scheme. To demonstrate the potential of such composite materials and the building process itself, a 1:1 lightweight module was constructed as an architectural prototype.