Karen Stinson remembers her little brother Charles building tiny houses under the dining room table at their home in Red Wing, Minn. He grew up to become the renowned architect Charles Stinson, who has designed projects from Costa Rica to Dubai and owns an architecture firm in Deephaven.

“My dream had always been to have my brother design a house for me,” she said.

Last year, that dream came true when Charles and his son Jason Stinson designed and built a modern flat-roofed home outfitted with solar panels in Minneapolis for Karen and her husband, Lee Larson. It’s custom-fit for the empty nesters to host sprawling family gatherings. “Every Friday night we host a family dinner with about 16 people,” Karen said. “We play mah-jongg on the patio, and the kids swim.”

It was serendipity that gave Karen and Lee the opportunity to finally live in a Stinson-designed house. They were content with their 1940s brick Tudor across from West River Parkway overlooking the Mississippi River. Then in 2005, the lot next door, which was very deep, was for sale. The couple decided to buy it as an investment, Lee said.

The next year they tore down a tiny ramshackle home on the property, planted wildflowers and let the land sit. They were focused on their demanding jobs and weren’t really sure what to do with the land. “We thought maybe one of our kids would want to build on it someday,” Karen said.

In 2007, Karen sold her Minneapolis consulting business, and the retired couple had more time to examine how and where they wanted to live in the future. They were committed to staying in their neighborhood, with its proximity to the river and bike trails they enjoy.

“We had this gorgeous city lot,” Karen said. “And we already had the builder and architect.”

Building on the lot next door gave the couple an opportunity to create a light-filled open floor plan, accessible features and flex spaces to accommodate their visiting children and grandchildren.

And they were completely on board with the trademark Stinson style — a flat roof, sleek horizontal lines and expanses of glass to draw in light all year long.

“Of course, we’d seen many of Charles’ houses,” Lee said. “We loved the clean lines and the way Charles ties the home to the environment.”

But for Charles, these clients were different. “I knew it had to be right, because I was going to be there every Thanksgiving,” he joked.

Over time, the family team “filled up a barge with ideas,” Charles said. His final design elegantly fulfilled Lee and Karen’s requests within an efficient 3,000 square feet.

The box-shaped home has one story for main living spaces and a partial second story for bedrooms over the attached garage.

“A full two-story would have been too massive and out of scale with the neighborhood,” Charles said. “This disguises some of the mass, but has a proportional sequence to it.”

The front and rear facades are punctuated by a stucco S-shaped outline that stands out against the dark cedar siding. “The S is a beautiful, simple form and makes a statement,” Charles said.

‘Connection to nature’

At the front entry, a welcoming courtyard beneath a stucco archway is where Karen and Lee sit and watch the joggers and bikers on the parkway, one of the home’s many features connecting occupants to the outdoors.

Inside, airy, open living spaces, combined with a glass wall, deliver a view of the Mediterranean blue saltwater pool and purple salvia in the back yard. High clerestory windows frame trees, clouds and rainstorms. When they step inside, visitors are surprised by the openness and panoramic pool view, Karen said.

“A house should create a sense of shelter,” Charles said, “but also a sense of release and connection to nature.”

Three sliding doors open to the pool and expansive back terrace. When the bugs come out, a drop-down 23-foot-long screened wall, activated by pushing a button, converts the terrace into a screen porch. “I got the idea when I saw a screened wall at a yoga retreat,” Charles said. Like many of the homes he designed while working in Florida, the open plan effortlessly flows from the inside to the outside and uses the site to create a private sanctuary.

The interior design reflects Charles’ warm modern aesthetic by juxtaposing natural materials, such as wood and stone, with layers of crisp horizontal lines. Dark walnut floors and cabinets create a striking backdrop for the cool blue and green palette, which plays off the azure pool and natural surroundings. A dropped ceiling over the dining room and kitchen defines the spaces without using a wall.

Charles inserted a whimsical walnut “tiki bar” in the corner of the living room where Lee mixes and serves beverages. “At first I thought it was a joke when Charles suggested it,” Lee said. “But it’s become a social area and really worked out.”

That leaves the generous-sized kitchen open for Karen and family members to prepare meals for holiday dinners. It’s equipped with sleek hardware-free Euro-style walnut cabinets that lift up and a two-tier Cambria-covered island for grandkids to snack and play with electronics. The edgy backsplash is made of back-painted glass that reflects light.

The second floor holds two bedrooms, as well as multi-functional spaces. The guest bedroom, with a pull-down Murphy bed, also doubles as a kids’ playroom. Karen’s office has a large computer desk on one end and exercise machines on the other end.

From the master suite, Karen and Lee can step out on a steel-railinged balcony overlooking the pool. “We love how this house lets nature in, which is important for mental and physical health,” she said. “We’re aware of the seasons all year long.”

Charles compared the home to a well-designed yacht or sailboat because “there’s a thoughtfulness to every inch,” he said. “With the craftsmanship and the built-in storage — there’s nothing wasted or redundant.” The home is full of space-saving efficient built-ins — from the beds to a hidden pantry that pulls out from the wall.

The couple also collaborated with Karen’s nephew Jason, who specializes in sustainable building, to incorporate as many green features as possible. “We want to leave the world a better place by the way we live,” Karen said. In addition to bamboo flooring, recycled wood and in-floor heat, there are 39 photovoltaic solar panels on the upper and lower roofs. The home has received the highest Minnesota Green Path rating.

“It’s a Stinson house,” Karen said. “But it’s still the essence of Lee and me.”

Even after friends warned her that the intense process could destroy her relationship with her brother, Karen never regretted her decision.

“Working with Charles and Jason was effortless because I knew they wanted to create the best possible house for us,” she said. “It was a fun experience.”

Charles agreed. “It was such a dream project,” he said. “I wish our parents were alive to see it.”