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Stucco or render is a material made of an adobe.
The difference in nomenclature between stucco, gypsum plaster.
Traditional stucco is made of glass fibers are added to improve the structural properties of the stucco. This is usually done with what is considered a one-coat stucco system, as opposed to the traditional three-coat method.
Lime stucco is a relatively solubility of lime (which in solution can be deposited in cracks, where it solidifies). Portland cement stucco is very hard and brittle and can easily crack if the base on which it is applied is not stable. Typically its color was gray, from the innate color of most Portland cement, but white Portland cement is also used. Today's stucco manufacturers offer a very wide range of colors that can be mixed integrally in the finish coat.
 Traditional stucco
As a building material, stucco is a durable, attractive, and weather-resistant wall covering. It was traditionally used as both an interior and exterior finish applied in one or two thin layers directly over a solid brick or stone surface. The finish coat usually contained an integral color and was typically textured for appearance.
Then with the introduction and development of heavy timber and light wood-framed construction methods, stucco was adapted for this new use by adding a reinforcement lattice, or lath, attached to and spanning between the structural supports and by increasing the thickness and number of layers of the total system. The lath added support for the wet plaster and tensile strength to the brittle, cured stucco; while the increased thickness and number of layers helped control cracking.
The traditional application of stucco and lath occurs in three coats — the scratch coat, the brown coat and the finish coat. The two base coats of plaster are either hand-applied or machine sprayed. The finish coat can be troweled smooth, hand-textured, floated to a sand finish or sprayed.
Originally the lath material was strips of wood installed horizontally on the wall, with spaces between, that would support the wet plaster until it cured. This lath and plaster technique became widely used.
In exterior wall applications, the lath is installed over a weather-resistant paper sheet that protects the framing from the moisture that can pass through the porous stucco.
Following Florida), stucco is the predominant exterior for both residential and commercial construction.
 Sculptural and architectural use
Stucco has also been used as a sculptural and artistic material. Stucco relief was used in the architectural decoration schemes of many ancient cultures. Examples of painting.
Since stucco can be used for decoration as well as for figurative representation, it provides an ideal transitive link from architectural details to Last Judgment at the center. Stucco is used to form a semi-plastic extension of the real architecture that merges into the painted architecture.
Indian architecture knows stucco as a material for sculpture in an architectural context. It is rare in the countryside.
Because of its "aristocratic" appearance, Baroque-looking stucco decoration was used frequently in upper-class apartments of the 19th and early 20th century.
Beginning in the 1920s, stucco, especially in its movement to remove the stucco from existing tenements.
Stucco was still employed in the 1950s in molded forms for decorating the joints between walls and ceilings inside houses. It was generally painted the same color as the ceiling and used in designs where a rat rail was in use.
 Modern stucco
Modern stucco is used as an exterior cement plaster wall covering. It is usually a mix of sand, Portland cement, lime and water, but may also consist of a proprietary mix of additives including fibers and synthetic acrylics that add strength and flexibility. Modern synthetic stucco can be applied as one base layer and a finish layer, which is thinner and faster to apply, compared to the traditional application of three-coat stucco.
As with any cement-based material, stucco must be reinforced to resist movement cracking. Plastic or wire mesh lath, attached with nails or screws to the structural framing, is embedded into the base coat to provided stiffening for the stucco. One method often used to help conceal the smaller surface cracks that may appear is the application of one of a variety of pre-mixed acrylic finishes. Flexible acrylic finishes have the ability to stretch and bridge over cracks, improving appearance and limiting the passage of moisture behind the stucco.
Where stucco is to be applied to a structure of wood-framing or light-gauge steel framing, the framing is protected from moisture damage by applying a vapor-permeable, water-resistant weather barrier; typically an building wraps" or "stucco wraps". The properties of the weather barrier must not only protect the framing from rain and moisture, but at the same time allow the free passage of any water vapor generated inside the building to escape through the wall.
A wide variety of stucco accessories, such as weep screeds, control and expansion joints, corner-aids and architectural reveals are sometimes also incorporated into the lath. Wire lath is used to give the plaster something to attach to and to add strength. Types include expanded-metal lath, woven-wire lath, and welded-wire lath.
The first layer of plaster is called a "scratch coat," consisting of plastic cement and sand. A trowel is used to scratch the surface horizontally or in a crisscross pattern to provide a key for the second layer. A brush is not used because it will cause delamination. The first coat is allowed to dry (cure) before the second layer is applied.
The next layer is called the "brown coat" or leveling coat. It also consists of sand, cement, and lime. It is leveled with tools called "darbies," "rods," and "feathereges," scraped smooth, and floated to provide a smooth, even surface onto which the finish coat is applied. It is then allowed to dry (cure) for 7–10 days minimum to allow "checking" (shrinkage) and cracking to take place.
If applied during very dry weather, the layers of stucco are sprayed with water for one or more days to keep a level of moisture within the stucco while it cures, a process known as "moist curing." If the stucco dries too soon, the chemical hardening ("hydration") will be incomplete, resulting in a weaker and brittler stucco.
The final, exterior layer is the "finish coat," of which there are two recommended types:
- Color Coat is a colored sand, cement, and lime mixed finish and is typically 3 mm (0.12 in) thick. It is applied over the second coat (brown coat) and can be floated with water for a sandy finish or textured over with a trowel to create various styles of finishes. Premixed, bagged stucco is gaining in use and is available in coarse graded sand and finer graded sand for creating a variety of troweled finishes; it is available in a variety of colors.
- Acrylic Finish is an acrylic-based finish from 1 to 4 mm (0.039 to 0.16 in) thick. It can be applied in many ways. It can be ordered in any color.
Hard Coating is another method of adding a finish to the stucco wall, although no longer recommended. In the 1960s and 1970s people added a variety of materials like glass chunks, stones or marble into the wet stucco wall. This kind of finish coat is very heavy and inflexible and is hard to repair.
 Stucco siding
Stucco is valued as a siding material for its attractiveness and durability and is a relatively low-maintenance exterior finish. It is often used on (but is certainly not limited to) Spanish-style homes. Stucco can be directly applied to brick and concrete, or applied to a lath (paper or wire mesh) over a wood frame or other material.
While nothing prevents anyone from painting or whitewashing concrete to make it look like stucco, paint generally does not adhere to concrete longer than two or three years, requiring constant re-application. Removing these materials in order to re-stucco requires expensive sandblasting. Paint also prevents the concrete from breathing. A stucco home can be refinished with an integral color stucco which does not require painting. Color can also be added to concrete when it is originally placed before curing, and thus the concrete would not require painting.
 See also
- Cement render
- Exterior insulation finishing system
- Lath and plaster
- Polished plaster
Emily Wadsworth, “Stucco Reliefs of the First and Second Centuries still Extant in Rome,” Memoirs of the American Academy in Rome 4 (1924) 9-102 Roger Ling, Stuccowork And Painting In Roman Italy, ed. Roger Ling (Aldershot : Ashgate, 1999)
- Anne Grimmer, The Preservation and Repair of Historic Stucco, published by the Technical Preservation Services, Heritage Preservation Services Division, National Park Service , and duplicated all over the web
- Italian stucco site
- About.com article on stucco
- Article about the history and process of Stucco homes
- German site on stucco
This article uses material from the Wikipedia article Stucco, which is released under the Creative Commons Attribution-Share-Alike License 3.0.