Traditional Stucco

Stucco is a material made of an aggregate, a binder, and water which is applied wet, and hardens when it dries. Also used in sidings, it is used as a coating for walls and ceilings and for decoration. In Europe the term render is more commonly used. Stucco may be used to cover less visually appealing construction materials such as concrete blocks, steel, or adobe.

Traditional stucco is made of lime, sand, and water. Modern stucco is made of Portland cement and water. Lime is often added to increase the permeability and workability of modern stucco. Sometimes additives such as acrylics and glass fibers are added to improve the structural properties of the plaster as well as its workability. This is usually done with what is considered a "one coat" stucco system—as opposed to the traditional 3 coat method.

Lime stucco is a relatively hard material that can be broken or chipped by hand without too much difficulty. The lime itself is usually white; color comes from the aggregate or any added pigments. Lime stucco has the property of being self-healing to a limited degree due to the slight solubility of lime (lime in solution can be deposited in cracks where it later solidifies). Portland cement stucco is very hard and brittle and can easily crack if the base on which it is applied is not stable. 

Traditionally stucco is directly applied to a masonry surface such as brick or stone. In wood-framed buildings, stucco was applied over a wood lath. Modern stucco is usually applied over an expanded metal lath that is fastened to the wall sheathing with staples, with a 2 layer moisture barrier in between.

Traditionally, stucco has been used as a sculptural and artistic material. Baroque and Rococo architecture makes heavy use of stucco. Examples can be found in churches and palaces, where stucco is mostly used to provide a smooth, decorative transition from walls to ceiling, decorating and giving measure to ceiling surfaces. Stucco is being used to form a semi-plastic extension of the real architecture that merges into the painted architecture.