Floating stairs and more at a Silicon Valley mansion

A three-story, 15,000-square-foot home nearing completion in the wealthy town of Los Altos Hills, Calif., is enjoying the decorative concrete treatment courtesy of Dave Pettigrew and his Capitola, Calif., outfit, Diamond D Concrete.

Pettigrew has installed several countertops in the mansion, all made with his signature bland of cement, silica sand and integral glass, and he's also stained floors. Perhaps most impressively, he's installed floating concrete stairways in two light wells at the house.





Each step of each stairway was cast in place, step by step, using a network of scaffolding. Formwork shaped steps that were 5 1/2 inches at one end, 3 inches at the other, and steel holds them in place. The initial plan called for precasting the steps, but they would have weighed 170 pounds each, Pettigrew says.




The stairs are stained with an auburn-colored acid stain that Pettigrew has custom-made for him by a chemist. Pettigrew turns to this chemist for many of his decorative concrete materials.






An outdoor BBQ table was created with cement, glass materials and shell fossils. An acid stain treatment colored the grout lines around each piece of glass, a contrast with the color visible through the glass pieces.






A "candy counter" was cast with cement and glass, but contains no rock or sand. It's in an entry room that leads to a 30-seat home theater in the basement. Pettigrew says his glass-based countertops are relatively good at resisting some foods, such as wine, that damage cementitious counters. "You don't have so seal them as much. Sealers cause me to get callback after callback after callback."








Floors in the house were inlaid with radiant heating, microtopped, troweled to get the swirly finish, and stained.






Pettigrew also delivered a counter made out of gray pigmented cement and clear glass for a back bar. The clear glass telegraphs the color of the cement throughout the piece.


Once his work at the house is finished (within the month) Pettigrew will be supplying Concrete Decor with more photos of Diamond D's work at this house. Watch for them.