How are intricate textures and patterns reproduced on architectural concrete surfaces?
The most common method is to produce a negative pattern in a thin, flexible plastic form liner. Such form liners need backup to support the pressures of the concrete so they are affixed to the interior surfaces of regular concrete forms. The plastic produces the required pattern, texture or gloss in the surface. Such form liners can be cleaned and reused many times. Blocks of foamed polystyrene can also be used after cutting, carving or sculpting to the desired shape. These are also used as form liners but are normally for single-use applications. Another method is to model the design in clay, from which a negative plaster mold is cast. The plaster mold is used only once. The field is wide open for developing other ingenious techniques.