Every custom home reflects site constraints, both physical and regulatory, but few occupy a tighter buildable envelope than Russian Hill. Its tiny infill lot, in the upscale San Francisco neighborhood of the same name, was subject not only to the city’s planning code and residential design guidelines, but also to easements—dating to a decades-old subdivision from the four adjacent properties—that imposed even more restrictive height and setback limitations. “It’s very unusual that we have a project that presses up against every possible limit,” says architect John Maniscalco, who nevertheless designed a house that turns every limitation to its advantage—and sports a LEED Platinum certification to boot.

“It’s a very compact site, and it’s surrounded on all sides,” Maniscalco says. Five neighboring houses directly abut the property. “And because all the houses have windows looking out on the site, there are interesting privacy issues, too,” he says. A steep side slope, commonplace in San Francisco, complicated matters at the ground plane, but the real issues were up above. Height limits varied from one part of the site to another, he says, “so we optimized downward,” stacking four stories at the front of the house and three at the rear and carving out a pair of recessed balconies, three elevated terraces, and a roof deck.

The street façade brings order to the house’s complex massing. Split-face limestone block, broken only by blind doors to the garage and a small entry courtyard, wraps the first floor, lending a sense of security at the sidewalk elevation and serving as a plinth for the stucco, steel, and glass elements above. San Francisco permits its famous bay windows to overhang the sidewalk, so Maniscalco designed an asymmetrical, plate-steel-clad version “to participate in the pattern of bay windows in a much more modern way.”

To buffer living spaces from the public, the garage and entry stair occupy the front half of the floor plan at street level. A family room stretches the width of the house at the rear, opening onto a compact, private garden with a fence of obscure-glass panels that, Maniscalco says, “kind of reverses the sense of enclosure.” Kitchen, dining, and living spaces fill the second floor, with a great room at the rear and formal dining and living areas at the front. The master bedroom and two children’s rooms are on the third floor, while the fourth floor holds an office and a media room, each with its own terrace, and access to the roof deck.

City views open progressively as one rises through the house, culminating in the roof deck’s 360-degree panorama. “You can see around the whole city,” Maniscalco says, “but the primary view is the entirety of the Golden Gate Bridge.” After paying due respect to those views—with room-width glazing at the north and south walls—he addressed a perennial challenge to Bay City architects: getting light into the center of the house. The entry stair, which rises through a skylight-topped volume, lends the adjacent living area “some two-story expansion,” he says, but the main event is a transverse stair hall that serves as an oversize light well. With roof windows above and glass-panel decks at the third and fourth floors, it channels daylight deep into the core of the building.

Exposed steel framing and glass railings give the central hall a bold visual character that contrasts with the house’s otherwise muted palette, and its welded plate-steel stair represents something of a technological tour de force. While each flight’s folded plane appears to float clear of its adjacent wall, every fourth riser extends into the wall, acting as a cantilevered beam. Walnut treads and railing caps weave the assembly into the material scheme of the surrounding space, while its low profile maximizes the transmission of light from above.

“One of the highlights of the project for me was fleshing out and finishing the stair design without blowing the budget,” says builder Derek Thompson. But the project’s ambitious green agenda yielded a long list of other accomplishments. “The biggest challenge,” he says, “was achieving LEED Platinum with a contemporary design.” As with any modern house, making it look easy is the hardest part, and many of this house’s notable features are hidden. The photovoltaic panels that feed electricity back to the grid lie flat atop the highest roof. Every drop of rain that falls on the building flows into a 1,500-gallon tank buried beneath the garage slab, for use in landscape irrigation. And the invisible feature of air quality drew special attention. “We do blower door tests before the drywall goes on, and that house performed incredibly high,” Thompson says. “It also has whole-house air filtration. It’s basically scrubbing the air throughout the house.”

“It’s a pretty sophisticated living environment,” notes Maniscalco, who specified fingerprint-detection entry locks, automatic window shades that track the sun’s path through the sky, and lighting, A/V, and alarm systems that can be controlled remotely via smartphone. “There’s a TV inside the master bathroom shower,” he adds, “behind the mirror.” But none of those bells and whistles eclipse Russian Hill’s most sophisticated dimension: its control of material, light, and geometry on a site that was as difficult as it was promising. “It’s not a design that allows a lot of tolerance,” Maniscalco says. “There’s a precision that comes from the core outward.”