Architectural as-cast concrete is among the most demanding of concrete finishes. But to then require that concrete to incorporate 30% fly ash as part of a LEED Platinum building adds a layer of complexity. That’s what McCarthy Building Companies faced on this new 45,000 square foot laboratory. Luckily for them, they had the services of Eddie Perez who had also worked on the architectural concrete at the Salk Institute and the Los Angeles Cathedral. “This was 8000-psi, fully-plasticized concrete,” says Perez. “We had to use 4x7-foot form panels with only 2 ties/sheet, so the formwork had to be built to be extremely stiff.” Perez was concerned about some surface blotchiness that showed up in early trials due to the fly ash. But using water-tight forms, epoxy-coated panels, and taking extreme care with form preparation has resulted in excellent finishes.