THE OLD four-square was OK. The location, a few bike-pedal pumps from Capitol Hill (and Trader Joe's, no less), was better.

But for architect Brad Khouri, it was the lot that had a lot to offer.

What he saw there in the overgrown blackberry patch of a yard was space for three families where, since 1904, there had been but one. Khouri quick-fixed the four-square for his own young family (remodeled kitchen and bath, insulation, fresh paint), then set about drawing for the backyard the sustainably-minded and affordable duplex he calls urban share.

His new neighbors moved in last summer. They all share the Drivable Grass driveway and an enthusiasm for urban living. After that it's different stories.

"I'm glad I got the chance to make a place of my own," says Marti Reddington.

She met Khouri of b9 architects at an open house for another town-home project of his in the Central District. She was 56, getting a divorce and needing a place of her own. She and her husband, an architect, had renovated and lived in eight houses over the course of their marriage. Reddington sent herself to cabinet and carpentry school "so I could have my say on the projects, still raise my kids and be on site.

"I thought it was exciting," she says of Khouri's thoughts on higher-density urban living. "I liked his ideas about community and privacy within it; that either way was comfortable."

When Khouri called her about his plan to subdivide his own property, Reddington was in before pencil hit paper. She was able to have a big say in her half of urban share; 1,135 square feet over three floors with one bedroom, a studio, two baths. "It sort of gave me a dream," she says.

"I have lots of design ideas. I once saw a gutted town house, and you could see between the floors. It was like balconies, like an opera set. That openness offered places of interaction within the house. And every place I've worked on I've tried to poke holes in it. So that's what this is."

"This" is a steel grill embedded into either the floor of her upstairs bedroom or into the ceiling of her living room, depending how you look at it.

"It throws these great shadows, and when I lie on the couch, I don't know, I just like it, the openness. Brad understood all that."

Next door, Sarah and Andrew Buhayar are settling into their first home after renting in Wallingford. At first they sought to buy a single-family home, but their budget said no. The couple, in their early 30s, found their half of urban share, in construction, on Redfin. Work brought the couple to Seattle from Chicago: She for the Bill & Melinda Gates Foundation, he for NBBJ.

Like Reddington, the Buhayars have Ikea kitchen cabinets, Paperstone counters and wood floors from fallen madrone trees. Solar preheat systems supply hot water to on-demand water heaters for domestic and radiant heat. Both homes have small backyards and recycled-brick patios. The Buhayar home is stacked perpendicular to Reddington's, wide where hers is long; their big views open to the Olympic Mountains (Rainier framed in a tall kitchen window). There are two bedrooms and two baths over 1,113 square feet. The couple cut their living space by half from the rental.

Sarah and Andrew tell their story in he-said, she-said fashion.

"When friends come over they assume we picked out everything. I love that crazy color green," Sarah says, glancing back to the chartreuse kitchen wall. "We came up here, we saw the Olympics, and we were sold."

"We were looking to buy a house, and we wanted to be central to walk and bike to work.

"Initially we poo-pooed town houses," Andrew says.

"All cookie-cutter, on alleys," Sarah says. "But this was different."

"There are a lot of windows, and great windows," Andrew says.

"And a lot of the town houses we looked at pretended they weren't right on top of each other. This is honest. We wave across at Brad and just say hi."

Both neighbors like living smart and no larger than their spaces allow.

"The longer I live here, I just keep working out how to live more vertically and to find hidden space," says Reddington.

"I had so many books, 50 boxes probably," Sarah says. "Moving into this place I got rid of most of them. That was initially hard."

"But we took them to Half Price Books and got a couple hundred dollars toward this chair," Andrew says.

"Our first furniture purchase, a Harry Bertoia chair," Sarah says. "I sit there in the mornings with my coffee and look at the mountains. I'm surprised how much I love the view. It's different every day."

Rebecca Teagarden writes about architecture and design for Pacific NW magazine. Benjamin Benschneider is a magazine staff photographer.