Local Berkshires limestone yields a slow-set lime putty that bonds cleanly with 19th-century brick. Carbonation proceeds at 0.5–1 mm per month under controlled humidity. Old mill walls show distinct stratification: original lime, gypsum repairs, and modern acrylic overlays that must be removed first.
Hoosic River aggregates add subtle grit for texture. Pigment integration works best with earth ochres applied in the final wash layers.