Like many new homeowners, Kevin Sawyers and Peter Steinauer knew they wanted to make some changes when they bought a house in the Dolores Heights neighborhood of San Francisco in 2015.

And as an interior designer, Mr. Sawyers, now 53, the founder of Sawyers Design, figured he might go further than most in updating the look of the place. (Mr. Steinauer, 51, is a software engineer at Apple.) But even he didn’t realize how much the project would eventually expand — that it would include a top-to-bottom, almost total rebuild of the house.

“It was very rustic, with a lot of wood, and sort of dilapidated,” Mr. Sawyers said. The house had been updated and expanded in fits and starts after the original portion was built in the early 1900s, which had created an awkward hodgepodge of architectural styles.

Nevertheless, he and Mr. Steinauer liked the way the home was set back from the street on a steep hill, and they were awe-struck by the enormous Monterey cypress tree in the backyard. They bought the property for $2.1 million that March, knowing that the loose floor tiles, beige carpeting and 1970s appliances would all have to go.

“I wanted to put a modern layer on the house, for sure,” Mr. Sawyers said. “I had grand ideas for what we could do on the inside — basically gutting it, which we did — but everything eventually changed on the exterior, too.”

The couple moved in before starting the renovation, and the longer they lived there, the more they sensed opportunities to make some big architectural moves. For help, Mr. Sawyers contacted Hulett Jones, a partner at the architecture firm Jones Haydu, whom he had worked with at the architecture and design firm Gensler before the two founded their own studios.

“I went with an architect instead of just trying to do it on my own, because I did want that bigger vision,” Mr. Sawyers said. “I had some ideas about what it could be, but they really just took it somewhere else and created a much larger project than we had anticipated.”

The footprint of the house, which wouldn’t be permitted under current zoning regulations, provided some unique opportunities, Mr. Jones said: “The nice thing about the house being sited at the rear of the property is that it gets these amazing views downtown and north, and great views from different angles, which became a driving factor of the design.” He and his partner, Paul Haydu, also wanted to create sightlines to the big tree in back.

Jones Haydu eliminated many interior walls and added new floor-to-ceiling windows, along with decks at various levels, to open up the home. At the first floor, which was elevated above the street and had been used as a stand-alone workshop, they added a cantilevered addition on the front that contains a guest suite and shades a new patio below. Behind the guest suite, they designed space for Mr. Sawyers’s home office, which is large enough to accommodate a few employees, and added a staircase that connects it to the rest of the house.

In the second-floor living room, they blew out walls that had just a few windows and replaced them with floor-to-ceiling expanses of glass under a cathedral ceiling, again pushing a few feet closer to the street. To create more headroom for the third-floor primary suite, they raised the roof and changed its pitch. In the primary bathroom, they positioned a free-standing tub in a nook with glass walls.

“That’s probably my No. 1 favorite thing in the house,” Mr. Sawyers said. “You’re sitting in the tub and can look out the window up to Twin Peaks. It just makes you feel like you’re in this glass box.”

For exterior cladding, Jones Haydu replaced the old cedar-shingle siding with a mix of standing-seam metal, used as roofing and siding, and cedar slats.

With such a modern, clean-lined architectural envelope, one might expect a series of pristine white boxes inside. But that wasn’t going to happen on Mr. Sawyers’s watch. To create a personal color palette, he drew inspiration from unusual sources: a luxurious Tibetan coat and the sets of the 1980 movie “American Gigolo.”

“I was thinking about making ourselves look and feel as good in this home as we could,” Mr. Sawyers said, much the way the sets in “American Gigolo” flattered Richard Gere. “I wanted to create this set that was for us — for me and Pete.”

The result includes walls painted in Benjamin Moore colors like Grape Juice (inspired by the saturated tones in some of the movie scenes); kitchen cabinets finished in teal (which served as a foil for the warm colors, as it did in the movie); a leafy wallpaper mural on one kitchen wall; and a living room fireplace surround of Phillip Jeffries grasscloth painted with gauzy clouds.

It took two years of construction, at a cost of more than $1,000 a square foot, but the couple finally moved back in to their largely rebuilt 3,200-square-foot home in September 2020, confident that they had created a one-of-a-kind gem.

“It’s fun, it’s open and it embraces the outside as much as possible,” Mr. Sawyers said. It’s also filled with unexpected personal touches, which is the point: “It just really fits our lifestyle.”

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