Straight from the horse's — er, umm, well ...
I was surprised to learn that the thick, adobe walls of the most ancient buildings in Cuenca—a colonial Andean city in Ecuador—were finished with multiple coats of clay.
This is the Catedral de Cuenca. The final coat, or paper-thin color-coat, was a paste of the finest mud blended with horse dung.
Like the fiberglass shreds mixed with concrete, the digested grass fibers in the horse shit provide binder, which prevents the plaster—or in this case, clay—from cracking when it dries.
— Fernando Pagés Ruiz is ProTradeCraft's Latin America Editor. He is currently building a business in Ecuador and a house in Mexico. Formerly, he was a builder in the Great Plains and mountain states. He is author of Building an Affordable House and Affordable Remodel (Taunton Press).