Plaster is an interior finish that aids in noise reduction and fireproofing and can be an integral aspect of a historic interior. A variety of plaster types have been used throughout history, characterized by composition and application. The most common constituents are gypsum, lime, or cement materials to form the matrix, blended with fine aggregates and fibers, depending on the application.

For flat and detailed surfaces like walls, ceilings and cornices, plaster is commonly mixed and formed onsite or pre-cast and installed. In these applications, the material is applied wet and finished when hardened as an interior finish primarily for walls and ceilings. Historically, plaster would serve as a surface finish or as a substrate for paint or wallpaper. Ornamental elements are typically cast into molds and applied to an architectural surface after curing.

Specialty ornamental plasters like Scagliola and Composition Ornament flourished between the 17th and 19th centuries and were often created to imitate stone and carved woodwork. These plasters used a variety of recipes and additives like animal glue and pigments to augment properties like moldability, strength, color, and aesthetics.

Repair and Restoration Best Practices

Prior to repairing, replacing, or restoring existing plaster, sources of deterioration should be addressed and mitigated. Moisture infiltration is one of the major and most common sources of deterioration for plaster. Therefore, maintaining the building structure around existing plaster is one of the primary ways to protect it from major deterioration and the need for replacement.

Refer to our restoration best practices page for additional information, details, and resources. Below, find plaster repair and restoration options for consideration on your project. 

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Here are some additional resources that focus on plaster repair and restoration. For a more comprehensive list of repair and restoration resources, please refer to the restoration page. For additional guidance, contact IMI. 


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