stucco_FAQ_cement
Stucco is a combination of cementitious ingredient(s), aggregate, and water. Other materials are sometimes added to enhance performance of the fresh or hardened plaster.

Stucco is a combination of cementitious ingredient(s), aggregate, and water. Other materials are sometimes added to enhance performance of the fresh or hardened plaster.

Cements for Stucco

  • portland cement (ASTM C 150, ASTM C 1157, or CSA A3001)
  • white portland cement (ASTM C 150, CSA A3001)
  • masonry cement (ASTM C 91, CSA A3002)
  • blended cement (ASTM C 595, ASTM C 1157, or CSA A3001)
  • plastic cement (ASTM C 1328) is primarily available in the west and southwestern United States

Fine aggregate, or sand, makes up the bulk of the volume of plaster. Its grains are cemented together by the paste. It usually meets the ASTM C 897 specification, though other gradations are allowed when plaster will be applied by hand (not machine).

Standards for Materials for Plaster

  • ASTM C 91, Standard Specification for Masonry Cement
  • ASTM C 150, Standard Specification for Portland Cement
  • ASTM C 207, Standard Specification for Hydrated Lime for Masonry Purposes
  • ASTM C 595, Standard Specification for Blended Hydraulic Cements
  • ASTM C 897, Standard Specification for Aggregates for Job-Mixed Portland Cement-Based Plasters
  • ASTM C 979, Specification for Pigments for Integrally Colored Concrete
  • ASTM C 1157, Standard Performance Specification for Hydraulic Cement
  • ASTM C 1328, Standard Specification for Plastic (Stucco) Cement
  • CSA A3001, Cementitious Materials for Use in Concrete
  • CSA A3002, Masonry Cement

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Installation Standards

There are two main standards organizations in North America, the American Society for Testing and Materials (ASTM) and the Canadian Standards Association (CSA). ASTM generates consensus documents with the input of many people, including contractors, engineers, architects, and material producers/suppliers. They agree on what constitutes “best practice” and develop standards to reflect that. These documents cover the ingredients and the application of portland cement plaster, or stucco. More.

Performance

Exterior portland cement plaster is subject to all types of weather conditions, from hot to cold and wet to dry. The weather-resistant finish is durable in all climates. Certain aspects of performance are highlighted here. More.