ABSTRACT
The roots of architectural terra cotta can be found in the ways that fired clay was used as a weathering surface differentiated from the body of the building underneath. Examples range from the walls of Babylon, to Etruscan temples, to British mathematical tiles. The name, terra cotta, dates from the eighteenth century. The success of terra cotta derives from the unique properties of clay, ultra-fine soils that are plastic when damp and form a rock-like mass when fired. Distinctive clays come from specific geographic locations but are now shipped as needed to manufacturing locations that may or may not be nearby. Clays are prepared and mixed using recipes that control the firing temperature, strength, hardness, porosity, color and shrinkage. The recipes must also suit the chosen manufacturing processes and must be replicable to assure quality products.
