architect: Fougeron Architecture, San Francisco

project: Tehama Grasshopper, San Francisco

detail: Windows

With its access to the sky and spectacular views of downtown San Francisco, this bedroom penthouse addition is the crown jewel of a loft renovation in an abandoned-warehouse district. In creating the master suite, Anne Fougeron, AIA, envisioned something gloriously light and airy, with shapes that break free of the rigid geometry of the building below.

Those ideas are expressed in a grasshopperlike volume created by rooflines that shoot up toward the views. The glass wall on the northwest-facing side reinforces the sense of a fiitting creature at rest. One section folds horizontally along the 8-foot-wide seat at the top of the stairs, creating a magical perch with a bird's-eye view of the city. Its glass was siliconed into a frame made from flat steel plates and steel rods screwed together. In fact, the frame is part of the light steel system supporting the penthouse on top of the concrete building.

“The reason we did this custom system was to keep the profiles as thin as possible so as not to interrupt the views,” says project designer Todd Aranaz. “Part of the inspiration came from the windows below in the existing 1940s building, which are light steel frames also.” The glass wall continuing beyond the window seat is canted slightly along a single plane. Part of the same steel system, it's fitted with custom-made aluminum frames with a thermal barrier. The aluminum frames were chosen for their insulating value and because they're rated for high winds, which can reach 80 mph up on the roof, Aranaz says.

general contractor: Johnstone McAuliffe Construction, Pacifica, Calif.

custom steel window fabricator: Dennis Luedeman, Emeryville, Calif.

materials: Insulated glass, custom steel frames, aluminum frames, threaded rods

photography: Richard Barnes