Nothing says Atomic Age like a bomb shelter in the basement. Nate Anderson has an original one, complete with bunk beds, in his 1957 walkout rambler in Minnetonka.

But the bomb shelter is just about the only thing he hasn’t changed in the 11 years since he bought the house. It was in foreclosure; some rooms had been gutted, and others had updates that clashed with the home’s original character.

“They weren’t period-appropriate,” he said. But he’d been looking for the right midcentury modern home for almost two years, and he thought this one had potential.

“You could see that the bones were well built,” he said. And the setting, a peaceful, wooded 2/3 acre set on a pond, was especially appealing to Anderson, a landscape architect. “It was an opportunity to flex my creativity,” he said of the house. “The midcentury modern era was an explosion of creativity.”

Anderson’s “Atomic Ranch Revival” is one of nine midcentury modern homes that will be open to visitors Oct. 12 during the annual fall tour presented by Docomomo, a modernist preservation group.

Several of the homes on the tour were designed by notable architects, including Ralph Rapson, Elizabeth Close and Arthur Dickey. Some have been gently updated; others have been completely transformed, but all illustrate “mindful renovation,” said Ben Clasen, vice president of the local chapter.

Anderson, for one, was extremely mindful of his home’s 1950s roots while he redesigned it for life today.

His new kitchen, for example, features a soffit detail that echoes the home’s original angles. He chose quartersawn red oak for his new cabinets because the tight grain resembled the original woodwork. The new vaulted ceiling is tongue-and-groove cedar, to match the rest of the main floor. Floating shelves, designed by Anderson, boomerang-shaped hardware and an orange Formica countertop complete the retro look.

“That was a debate,” Anderson admitted. “I like the durability of Formica. Period-wise, it’s very appropriate.” And the juicy hue adds a playful pop of color.

In his living room, the fireplace is clad in blond brick that looks like it could be original — but isn’t.

The fireplace surround had been drywalled. Anderson removed it to find brick beneath. But the brick was in poor condition and wasn’t worth showcasing. So he chose new Norman brick veneer, a long, narrow style that was popular in midcentury homes.

For lighting, he scoured Craigslist and estate sales to find vintage fixtures.

The 2,300-square-foot home gives Anderson space to display his collection of midcentury modern dinnerware. It’s also the perfect setting for his midcentury furniture. “Most of it is vintage, accumulated over time,” he said. New pieces, including his Room & Board sectional, were carefully chosen because their simplicity complements the style of the era.

Anderson’s retro jewel is now seeking a new owner. Due to a job opportunity in Winona, Minn., he recently listed the house for $629,000. “I have mixed emotions,” he said of selling his creation. “It’s bittersweet.” Opening it for the tour and interacting with visitors will be a final way to celebrate the house and its revival. “It’s a good feeling to share it before I give it up,” he said.

Rebooting ‘the bunker’

Jay Isenberg and his wife, Lynda Monick-Isenberg, also found a midcentury home in foreclosure that they recently reinvented into a striking 21st-century home.

The couple bought the concrete-block split-level in Golden Valley in 2016.

“We called it the concrete bunker,” said Isenberg, an architect. The small house had been vacant for a year and a half and needed a lot of work.

“Any normal person would have demo’d it,” Isenberg said. Their initial plan was to flip the house after making some enhancements. But as they explored the home’s possibilities, they ultimately decided to transform it for themselves.

“It became a catalyst to sell our existing house near Cedar Lake,” Isenberg said, one they’d designed, built and lived in for more than three decades. “The more I thought about it, the more appealing it was.”

Within three weeks of closing on the house, a crew gutted it to the studs to create “a blank palette.”

In addition to serving as his own architect, Isenberg also assumed the role of general contractor, which was more challenging than he’d anticipated. “This was not my first rodeo,” he said. “I have designed, developed, built, collaborated and flipped dozens of houses in the Twin Cities.”

But managing every detail, from subcontractors to schedules, was daunting. “It was an adventure,” he said. “There were many surprises and unexpected things.”

Isenberg designed a two-story addition that created space for a master bedroom and loft-style studio above and a sitting room below. Both he and his wife, an artist and educator, work from home and share the studio space. They also added a three-season porch.

The original house had an appealing open floor plan. “There was no reason to change that,” he said. But the dark-stained cedar interiors made the whole house feel dark, so they were painted white. “We wanted it light-filled.”

A new kitchen with an island occupies the same footprint as the original one, but it’s now more open to the living area and defined by timber columns.

The couple tried to save their original concrete corner fireplace in the living room. “We spent weeks trying to make that work,” said Isenberg of incorporating it into the new, expanded floor plan. In the end, they sliced off 2 feet of masonry to make the fireplace less deep, and added a gas insert.

Staying on budget and making trade-offs about where to splurge and where to save was another challenge, Isenberg said. Splurges included quartzite countertops, a new staircase with cable railings, a steel ledge, maple veneer flooring to replace the carpet and high-quality windows.

The yearlong project was worth the effort. “Absolutely!” said Isenberg. “We came to love the house. It’s the right size for us, and we love the openness.”

They especially love their bright-red porch. “We live in there from May through October. Our Red Folly, Lynda calls it,” he said.

“The house became a vessel for the way we live,” Isenberg said. “It’s a fun house — not a serious piece of work. It’s a place to be happy.”