In January, Mohler and his wife, Jill Fresonke, and their 7-month-old son, Jackson, moved into the owners' section of their split-use dwelling in the Latona district, just east of Green Lake. Mohler has nicknamed it the Flip-Flop House because although the owners' unit and the rental section share one building and are configured similarly, the living areas face in opposite directions.

"The most commonly found scenario in Seattle is the basement apartment," Mohler explains. "There are acoustic problems. And often, because there frequently are sloping sites, the tenant winds up having the garden. I tried to set this up so we would both have a private entrance, and a feeling of two houses and private ownership."

He also wanted the house to relate to its corner site. "That started the relationship of diagonals: the two yards, the two entrances, which are diagonally opposed," he says. "Entrances are a challenge on a corner site; every side of the house is visible."

Rick Mohler, his wife, Jill Fresonke, and their son, Jackson, share a quiet moment in the kitchen of their new home. Mohler feels Seattle is ready for well-designed "accessory dwelling units" built with quality materials.

The way his home relates to its site explains how Mohler thinks about architecture. As an associate professor in the architecture department at the University of Washington, he team-teaches graduate students. "We try to get them to think about how architecture really is about enclosure. Architecture is not so much about things as it is about the relationship between things, between indoor and outdoor spaces. For this project, the hope was to have the entire site be seen as a series of rooms."

Mohler is a principal in the Seattle architecture firm of Adams Mohler Ghillino, which has earned a number of design awards for residential and commercial projects, including an American Institute of Architects regional Honor Award in 2002 for its makeover of the venerable Stable Building, just east of downtown Seattle on 20th Avenue.

The living room is comfortable enough for one person to hang out in, but equally fine for a large party. The window wall, left, has doors that open to a broad deck. A curtain controls sunlight. The steel support, right, is a functional part of the décor.

High-quality shared residences, Mohler believes, may be one of the more painless ways for Seattle neighborhoods to absorb growth. He hopes his project will inspire clients to consider the option.

So far as the city is concerned, this single-family residence on a 6,200-square-foot lot with an attached accessory dwelling unit (ADU) is a welcome addition to the neighborhood. Seattle's land-use goals, as spelled out in a February 2004 report, encourage development of unattached and attached ADUs to diversify housing supplies in residential neighborhoods. According to the Department of Planning and Development data, as of that date, there were 1,200 ADUs in the city with final permits. (By contrast, San Diego reportedly received just 14 such applications in the past 20 years.)

The modernist-style exterior design of the Mohler house is visually intriguing, with blue corrugated sheet-metal siding below square-cut fiber-cement panels, and glass that meets the roofline and turns with the corners. The strong horizontal lines of the siding, roofline and upper-floor windows pull this large building closer to the ground.

Mohler, whose first job out of architecture school was in Robert Venturi’s firm in Philadelphia, runs to keep in shape. So far as design is concerned, "you always want to be learning. You always want to be pushing yourself to try something you haven’t tried before."

The front door to the owners' part of the house is at the southeast corner, in a sheltered portico. From across the street, the porch looks as if a block in a puzzle cube had been moved up and suspended to shelter the entryway. Large glue-lam beams support this upper-floor section, which cantilevers out. The rental's entry has a similar cantilevered segment.

The owners' part of the house is about 3,000 square feet, with three bedrooms, 2 ½ baths. The rental unit has two bedrooms and a large, open living area in just less than 1,000 square feet. Both ends of the building have territorial views and access to a garden. These neighbors will share the basement garage, but no other common areas.

The owners' kitchen is left of the entry, open to the rest of the living area. Two built-in fir bookcases frame a fireplace on the opposite end of the room.

Corner windows, placed high for privacy, light the stairwell up to second-floor bedrooms. Waxed blackened steel contrasts with light-toned bamboo steps and fir railings, adding musicality to the scene.

Per code requirements, a bit of wall between the units is shared. Here, it's a portion at the fireplace extending behind the closets in an upstairs bedroom. Sounds from next door stay next door.

A west-facing glass wall brings the outside in — especially since three sets of doors fold back to create free-flowing space to a wide deck, extending use of the living room to what functions as a series of terraces.

The space is light and bright, and the 9-foot ceilings on the ground floor seem a couple of feet higher, thanks to clever use of transom windows above doors and a row of panes where the window wall meets the ceiling. Large windows wrap the upper corners of the stairwell, providing a view over housetops while preserving privacy.

Mohler says of the master-bedroom windows: "I've often seen owners kind of delude themselves. They ignore . . . cost because they want something. And I've done exactly the same thing with these windows." Jackson looks to be less pensive.

Finish work is top-notch, and includes clear-fir banister railings and custom ironwork for the stairway. Countertops are PaperStone, a paper-based product that has a sheen like oiled black slate; it's made by Puyallup-based KlipTech Composites. Mohler chose Lindal Cedar Homes to fabricate the wood-frame windows. E.R. Properties was the building contractor.

Mohler finds the neighborhood a good fit. It's close to the UW and convenient for Jill, who is a naturopathic physician at the Bastyr Center for Natural Health in Wallingford. Because they're both avid runners, proximity to Green Lake is another plus.

Not unexpectedly, Mohler found it much more challenging to design for himself than for a client. "There's the whole issue of it conveying what you really believe in architecture. You just have to power through that.

The owners' residence is lit by afternoon winter sunlight, while the accessory dwelling unit, at left, is angled to face sunrises. Mohler was relieved to be able to spare the large conifer that anchors the south end of the lot.

"And I have a tremendous amount of empathy for clients now. When it's your own house, you do find you are second-guessing details because you know you are going to have to live with it."

Dean Stahl is a Seattle free-lance writer. He can be reached at docent@mac.com. Benjamin Benschneider is a Pacific Northwest magazine staff photographer.