 Framing walls were 18 inches (45.7 centimeters) thick.The building is constructed of longleaf pine framing, with walls of oyster-shell concrete in the oldest construction and with bousillage of clay and Spanish moss in the western and most recent addition.Dendrochronology has been used to date timbers from the center tabby room to 1757; samples from the east tabby addition date to 1762 and 1772.