Preservation Brief 42, The Maintenance, Repair and Replacement of Historic Cast Stone

Summary

This is number forty-two of 42 preservation briefs prepared by the Technical Preservation Services of the National Park Service. This brief focuses on the maintenance, repair and replacement of historic cast stone.

Cast stone-a mixture of water, sand, coarse aggregate, and cementing agents--has proven over time to be an attractive and durable building material, when properly manufactured. It gained popularity in the 1860s and, by the early decades of the 20th century, became widely accepted as an economical substitute for natural stone. Unfortunately, much historic cast stone is unnecessarily replaced when it could easily be repaired and preserved in situ, or left untreated. Appropriate repair of damaged units can extend the life of any cast stone installation. Because of the necessity of matching both matrix color and aggregate size and ratio, conservation projects which involve repair or replication of cast stone should allow adequate lead time for the assembly of materials and the preparation of test samples. Understanding which conditions require repair, which warrant replacement, and which should be accepted as normal weathering is key to selecting the most appropriate approach to the protection and care of historic cast stone.

Keywords

Individual & Institutional Roles

Contact(s): Cultural Resource Office, Joint Base San Antonio

Project Director(s): Kay D. Weeks

Repository(s): Fort Sam Houston

Prepared By(s): Technical Preservation Services, Heritage Preservation Services Program, National Park Service

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