SEATTLE — By its very nature, a “concept” is intangibly abstract: a notion, an idea, a feeling. Certainly not anything you can see, or hold, or assemble.

But nature adapts. And now, in one ever-evolving Seattle ecosystem, 28 people in nine families are living in an ultra-collaborative community that is so concretely conceptual, it is practically, and purposefully, built on trust.

This is Capitol Hill Urban Cohousing (CHUC), a modern-in-every-sense-of-the-word mixed-use building designed by married architects Grace Kim and Mike Mariano, founders of Schemata Workshop. (Their office is on CHUC’s ground floor; they live with 10-year-old daughter Ella on the fourth.)

With design features that promote everyday interaction and openness — a lively rooftop garden with a P-Patch and furnished deck, a central courtyard visible from all nine units through curtain-free windows, and a communal kitchen that hosts three organized community dinners a week — CHUC has stood as a solid representation of intentional, intergenerational community-building since its completion in 2016. This year, it also epitomizes the one-word theme of the 2018 Seattle Design Festival.

“Last year, the theme was ‘power,’” says Sarah Haase, chair of this year’s festival (she also works at Schemata Workshop). “This year, it’s ‘trust’: in our systems, experiences, public spaces, infrastructure. It’s essential that the public live in a sustainable, equitable city. That’s been called into question in Seattle, nationally and globally. We’re hoping to have a discourse: specifically, how design can elevate trust through the process and outcome, and the ways design could encourage it.”

Some urban design elements, Kim and Haase say, visibly discourage trust, like spikes on public benches, or any and all gates. (“I always hate gates,” says Kim. “They send a clear message of who belongs and who doesn’t in an unnecessary way.”)

But by its own nature, CHUC needed to build trust among its residents even before it was built.

Kim is an internationally regarded cohousing expert; she and Mariano studied the lifestyle extensively in Denmark and also designed Daybreak Cohousing in Portland. Kim wrote “Designing the Cohousing Common House,” and her TED Talk on cohousing has nearly 2 million views.

They’re also personally invested: They bought this 4,500-square-foot lot in 2008, and managed CHUC’s funding and acted as its developers as they “passively recruited” neighbors.

“We started in 2010 with four families and spent seven years building the group and processes,” says Kim. “To find the right person, we kissed a lot of frogs. More than that, they knew we were the right community. It naturally sorts itself out. There was a lot of trust and faith. Many times, we joked as a metaphor: ‘Here we are at the edge of a cliff; we’re all going to jump and hope we land.’”

Sheila Hoffman and Spencer Beard landed in a two-bedroom unit across the courtyard from Kim and her family. At 68 and 65, respectively, Hoffman says, “We are the seniors in the building.”

Before moving in, Beard says, as residents hammered out CHUC’s mission and policies, “We did a lot of work building communication skills; we spent more time on that than on the building. As problems came up, we all stayed in and trusted that the mind of the community would be greater than the mind of the individual. What we’ve learned over time is this trust is the underpinning of consensus: what’s best for the community. When we listen, we always, always come up with the best solution. There’s a lot of trust. When you think it’s not going to work out and it does, it feeds the trust.”

CHUC is owned in equal shares by all nine families — basically, the residents act as their own landlords, renting their units to themselves — so, “There was a lot of trust around the money,” says Kim: “Oh, my gosh; we’re going to take on this huge loan.”

Each family picked its own airy, eco-friendly unit as it joined CHUC (residences range in size from 810 to 1,300 square feet). “Our rents are on par with other units on Capitol Hill,” she says — but from there, CHUC’s design, mission and residents elevate the typical rental experience considerably.

“We’re all here with the intention to live collaboratively and in community; it’s different in an apartment complex,” says Kim. “In our (previous) condo downtown, there were seven units on our floor, and we’d try to host cocktails or brunch and only get the same one couple. It was friendly enough, but nobody moved in with the intent to build relationships.”

Here, Kim says, relationships continue to deepen, along with all kinds of trust: People leave their doors open, and call on neighbors often.

— There’s backup. “In November, one mom asked Ella to watch her 4-year-old,” Kim says. “Ella got to baby-sit, safe in our home, and she knew all the adults were downstairs. We appreciated the trust, trusting each other to ‘parent’ each other’s kids.”

— There’s reassurance. “Because we have the intention to live collaboratively, we’re going to figure out conflicts,” Kim says. “You can be vulnerable and see your behavior through someone else’s eyes; having that trust there for the long haul makes you more accountable. I feel very supported by living in this community.”

— And there’s security. Kim says Beard “was our go-to” when her daughter needed to be picked up. “With us, because we are the elders, we have more time. Spencer is retired; my home-based business is winding down,” Hoffman says. “We have a lot of flexibility. We hope we’re building enough social capital that others will remember when we’re old. There’s no guarantee, but we have some trust that people will be here for us.”

Like all the trust at the foundation of CHUC, it’s likely that investment will pay off.

“It feels like family here,” says Kim. “Everybody joined with the idea it’s not a temporary situation. A number assume we’ll live here till we die. When you have that kind of time, you have an expectation that things will work out. No one has moved out. I don’t see anybody leaving anytime soon.”