Stucco is a type of finishing plaster that is commonly used on the exterior of buildings, and has been used in construction for centuries in various forms. While it can also be used inside, specially designed interior plasters have replaced it for interior use in most regions. In ancient times, interior stucco would be made by mixing marble dust, lime, and water to create a smooth plaster which could be molded into elaborate scenes and painted. Spanish, Greek, and Mission style architecture all prominently feature stucco, which helps to reflect heat and keep homes cool.
A variety of materials can be used to make stucco. Traditional material uses lime, a substance made by baking limestone in kilns so that it calcifies, along with with sand and water. These elements are mixed into a paste which can be troweled onto a surface or molded, as used to be common with interior stucco. Stucco made in this fashion is durable, strong, and heavy. Because lime is somewhat soluble, cracks in the plaster will fix themselves, as the lime will drip to fill them if moistened. More commonly today, stucco uses finely ground Portland Cement, sand, and water, which results in a less durable form that easily cracks.
Stucco can be applied to a framework like chicken wire or wood, or it can be plastered over bricks and masonry, as long as they are roughened beforehand. Classically, this plaster is white, as can be seen in Spanish and Greek architecture. It can also be colored with the addition of pigments, as was done on ranch houses in the United States in the 1960s and 1970s. Once applied, stucco can be scraped smooth or textured with a tool or the introduction of rocks or vegetable matter.
Classical stucco is usually sturdy for the lifetime of the house. Synthetic and cheap replacements, however, are not. Stucco houses sometimes experience issues with rot in the underlying wood or cracking. For this reason, a home made with this material should be carefully inspected before purchase. If a new home is being built out of stucco, it is cost effective to spend more on high quality material so that the home does not have to be repaired later in life. Especially in hot regions, it is an excellent building material because it helps to regulate temperatures when the home is built right.
By Mary McMahon
Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a About Mechanics researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.