....................   Illustrated Architecture Dictionary



Any of a number of suitable surfaces for receiving plasterwork, as gypsum lath, metal lath, wood lath, masonry, or brickwork
Ornamental plasterwork

"Historically, ornamental plasterwork has been produced in two ways: it would be run in place (or on a bench) at the site; or cast in molds in a workshop. Plain plaster molding without surface ornamentation was usually created directly on the wall, or run on a flat surface such as a plasterer's workbench and attached to the wall after it set.

"Three decorative plaster forms in particular—the cornice, the ceiling medallion, and the coffered ceiling—historically comprised much of the ornamental plasterers' business.

"Ornament such as coffering for ceilings, centers for light fixtures (medallions), brackets, dentils, or columns were cast in hide glue (gelatin) or plaster molds in an offsite shop, often in more than one piece, then assembled and installed in the building. Decorative "enrichments" such as leaves, egg and dart moldings, and bead and reel units were cast in the shop and applied to the plain runs using plaster as an adhesive. Painting, glazing, and even gilding followed.
- David Flaharty, "Preserving Historic Ornamental Plaster"pub. on (online Nov. 2016)

Flat stucco embedded with pebbles for a texture effect.

A composition of gypsum or lime, water, sand, and sometimes hair or other fiber, applied in a pasty form to the surface of walls or ceilings in a plastic state and allowed to harden and dry
Portland cement

A hydraulic cement (cement that hardens under water)  made by heating limestone and clay in a kiln and pulverizing the result.  It is the most common type of cement in general use around the world. Named after Portland, an urban district of southern England.

In 1824, Englishmen, Joseph Aspdin patented Portland cement. Portland cement, as modern cement is called, is a mixture of limestone and clay, burned in a furnace and then pulverized. Impervious to water, it actually becomes stronger if submerged after it hardens. Samples of concrete taken thirty years after a concrete boat sank during World War I showed that the concrete had doubled its compressive strength.


"At the beginning of the 20th century, the Portland cement industry aggressively advertised their modern, fast-setting stucco as durable, fireproof, vermin resistant, maintenance free, and beautiful: a material to replace traditional exterior claddings. Cement stucco was used to remodel older homes and became a popular choice for new construction.

"Applied over wood lath, wire lath, or masonry, stucco is a versatile finish material for many building styles, offering the possibility of texture that varies from troweled smooth to coarse roughcast or pebbledash, which incorporates pebbles or shells. Stucco may be painted, but it was frequently tinted with pigments at application. Color and texture also came from the addition of mica, small stones, or sand." - Steve Jordon, Old House Online (online Jan. 2107)
Reinforced plaster

Materials such as cloth are included to strengthen plaster that is used, for example, in interior ornamentation.
Rubber molds

Typically used in reproducing plaster ornamentation.

Plaster Systems at Buffalo Plastering & Architectural Casting

Plasterwork imitating granite or marble

1. An exterior finish, usually textured; composed of portland cement, lime, and sand, which are mixed with water.
2. A fine plaster used for decorative work or moldings.

Stucco may be used to cover less visually appealing construction materials such as metal, concrete, cinder block, or clay brick and adobe.

Until the latter part of the nineteenth century, it was common that plaster was used inside a building, and stucco was used outside.

Sometimes additives such as acrylics and glass fibers are added to improve the structural properties of the stucco.

Stucco has been in use for centuries. The Romans used lime stucco on the interiors and exteriors of their buildings. In early America, lime and sand stucco was commonly used to decorate and to weatherproof masonry buildings. Lime stucco is a very different material from stucco made with Portland cement. Lime stuccos and mortars are prized for their soft qualities.(the material is sacrificial to the masonry) and their unique self-healing properties. Although Portland stucco contains lime, it is harder and it's brittle.

Page by Chuck LaChiusa in 2012
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