Sphinxstone

Deterioration of corner of Sphinxstone block
Courtesy of Citadel DCA

Description

[Sphinx Acoustical Company] An acoustic Cast stone produced by the Sphinx Acoustical Company. In 1934, Sphinxstone was used in the construction of the Mellon Auditorium in Washington DC. During restoration of the building, visual inspection of the deteriorated sections of the concrete blocks indicated they contain mollusk shells and white Portland. Other fillers and binders are unknown.

Sphinxstone label

Resources and Citations

• Lynn Scott Paden, Citadel DCA contributed information, June 2022.
• Richard Pieper, 'The Maintenance, Repair and Replacement of Historic Cast Stone' NPS, Technical Briefs #42 Link