A mould can be made for every shape. You can make the inverse shape of any object if you have the right knowledge, materials and tools. Making the right mould was not the objective of the Concretum workshop. The formal design did not determine the mould. Rather, it was the material of the mould that inspired the design. The interaction between mould and design can thus play out at different levels. The relation between shape, power and appearance plays a crucial role here.
The mould is a representation of the product. Hidden in the mould lies the shape of the product. The inner side of the mould must fix the shape of the concrete. During the workshop participants considered both the shape and its inverse shape. The mould is a design tool and enables the designer to reflect on the tectonics of his design. By physically making the mould, the designer is aware not only of the size and scale of the object but also of the complexity and the weight of the form. The idea is set in the size. Design themes result from experimentation with the textile mould: the double-curved surface (bridge), the relation between mould and shape (wooden boxes), the connecting of a module (lounge elements), and the undulating surface (wall).
The mould is the inverse shape not just in the formal sense. Structurally too, the mould is the opposite of the eventual object. The dry concrete and the steel engage in an interplay of forces, of tension and compression. As long as the concrete is still wet, the mould can absorb all forces. All the forces want to escape from the object as the concrete is being poured. The soft concrete wants to flow everywhere. Once dry, the object contains all the forces. Textile possesses interesting properties. In contrast to many materials that are used to make moulds, textile is not stiff but flexible. Accordingly, totally different shapes can be created. In addition, a textile mould can set up an interesting play of forces. Textile ‘gives’ under the weight of the concrete and dictates the shape and texture of the product in its own unique way. Because of this, a less fixed and more dynamic contact with the shape is possible.
The soft concrete adopts the texture of the textile. This texture is more than an imprint of the surface of the mould. You can actually read the forces in the texture. The ‘appearance’ of the concrete is determined not only by the imprint of the mould but equally by the visible play of forces: the smoothness, the imprints of the seams of the mould, the bubble that couldn’t escape, the bulging of a surface, and the folds in the fabric. Building at scale 1:1 means that the makers become aware of the thickness of the seam and of the edge. Concealed behind every line is a whole process of designing, making and building. The edge and the seam are no longer lines but surfaces that also have a texture and extend around the corner.
Coincidences such as the stretching, folding or creasing become part of the design. It is a matter of varying with the interplay of forces and allowing these to find their expression in the eventual shape, without actually dictating the exact shape in advance. Repetition, experience and intuition teach the maker what should and should not be fixed. The textile stimulates this testing and thinking about shapes, forces and appearances. In the end, every object divulges how its mould is made through its shape, seams, textures and edges. Exciting and inventive experiments are within reach when coincidence is admitted and freedom is pursued in a controlled manner.
by Machiel Spaan
Academie van Bouwkunst, Amsterdam