A mixture of portland cement, sand, fiber and small quantities of lime, to permit it to expand and contract without cracking, cement stucco provides a durable finish for exterior walls.
Usually applied in three coats over masonry materials such as concrete or concrete block, cement stucco forms a protective wall finish that resists assault from an assortment of forces, from wood-peckers to weed-eaters.
Cement stucco sheds water well and offers some vapor permeability, unless sealed with a waterproof paint, but it's not breathable like earthen, lime or gypsum plasters.
Cement stucco (one part cement, three parts sand) = 0.
An interesting note: the house was covered with earthen plaster until receiving a coat of cement stucco in 1930.
The cement stucco on the outside of the building is richly colored with ferric nitrate.