Materials and Assemblies

Understanding the materials and construction of existing buildings is fundamental to effective preservation, rehabilitation and capital planning. The performance of historic masonry, architectural terra cotta, stone, concrete, metals, wood, glazing and waterproofing systems is influenced by material properties, construction methods, environmental exposure and previous interventions.

These material guides examine construction and performance, common conditions and deterioration mechanisms, investigation requirements, preservation treatments and the commercial considerations associated with rehabilitation. Each guide connects technical information with construction scope, repair and replacement alternatives, procurement requirements, project costs and long-term maintenance.

The guides are organized into four sections: Materials Science; Conditions and Investigation; Preservation Treatments and Interventions; and Capital Planning and Owner Decisions. The National Park Service treatment framework informs preservation considerations but does not establish automatic repair recommendations.