Architectural Precast vs. Cast Stone

Architectural Precast is specified in section 03450 and generally used as large wall panels, columns, spandrels and other “structural” members with architectural finish. It is made with ingredients including white or grey cement and graded sieve aggregates typically 1” or smaller. The compression strength is approximately 5000 psi at 28 days. Architectural Precast is typically installed by the producer company or a contracted steel or precast erection company. The quality requirements for architectural precast are typically governed by the Precast/Prestressed Concrete Institute (PCI).

Cast Stone is specified in section 04720 and is a highly refined architectural precast building “stone”, similar in appearance and manufactured to simulate the color, texture and appearance of natural cut stone. It is the most aesthetically refined form of concrete known. Cast stone is used as a masonry product to provide architectural trim, ornamentation or functional features on buildings and other structures in various forms such caps, sills, bands, medallions, veneer panels and in many landscaping and monument applications with architectural finish. It is made with ingredients including white cement and graded sieve aggregates typically 1/2” or smaller. Cast Stone is a dense material with a finish more highly refined with less “bug holes”, commonly referred to as "sugar cube finish". Typical finishes for Cast Stone include acid etched, honed or polished. The compression strength is minimum 6500 psi at 28 days with a lower cold water absorption rate making it stronger and less permeable to water, weather and dirt than natural limestone or concrete. Cast stone will improve in appearance with decades of exposure to weathering and other atmospheric elements.The quality requirements for cast stone are typically governed by the Cast Stone Institute (CSI). This includes the provision for a 10-year product warranty on all cast stone products, specified to meet the CSI quality assurance manual.