A building material made from lime, gypsum, or cement mixed with water and sand to create smooth interior and exterior wall finishes.

Plaster is a building material made from lime, gypsum, or cement mixed with water and sand or other aggregates to create a smooth, durable finish for interior and exterior walls and ceilings. This versatile material has been used for thousands of years to provide protective and decorative surfaces that can be applied over various substrates including masonry, wood lath, metal lath, or gypsum board. Plaster offers excellent durability, fire resistance, and acoustic properties while allowing for intricate decorative treatments and smooth, seamless finishes that are difficult to achieve with other wall covering materials, making it a preferred choice for high-quality construction and restoration projects.

Plaster is used in various construction applications including interior wall and ceiling finishes in residential and commercial buildings where smooth, durable surfaces are desired, exterior stucco systems that provide weather protection and architectural character to building facades, restoration and preservation projects where historical accuracy and traditional materials are required, decorative applications such as ornamental moldings, cornices, and artistic relief work, and specialty installations including fire-rated assemblies, acoustic treatments, and high-abuse areas that require exceptional durability. Each application may require specific plaster formulations and application techniques based on the intended use and environmental conditions.

The types and composition of plaster include lime plaster made from lime putty, sand, and water that provides excellent workability and self-healing properties, gypsum plaster using calcined gypsum as the binder for interior applications where quick setting and smooth finishes are desired, cement plaster combining Portland cement, sand, and water for exterior applications requiring weather resistance and durability, clay plaster using natural clay as a binder for sustainable and breathable wall finishes, and specialty plasters such as venetian plaster, horsehair plaster, or polymer-modified systems designed for specific performance requirements.

Fun Fact: The oldest known plaster dates back over 9,000 years to Neolithic settlements in Turkey, where lime plaster was used to create smooth wall surfaces and even primitive mirrors by polishing the plaster to a high sheen.

• Gypsum Plaster
• Lath and Plaster
• Plaster Key