Tom and Darice Henritze’s backyard moves seamlessly from one season to the next, as easily as stepping through the open bulthaup kitchen, on to the Ipe deck and into the sunken outdoor lounge. Art inside and outside—from a photo series of the same tree 70 times (a friend’s thank-you gift for dinner) to the deity-sized Buddha head outside—provide design consistency. When it gets too chilly, floor-to-ceiling glass doors on the north and east walls slide shut, leaving a full view of the backyard unobstructed by things like door frames and drywall. “I feel like I’m living in the forest in this house and that’s very hard to find in the city of Denver,” said Darice, an accountant. “I just never imagined that I’d be living in a house where I didn’t feel like I was living in a house. I feel like I’m camping—really luxury camping.”

But this is no ordinary modern house. It’s one of the crown jewels of Arapahoe Acres, Denver’s most recognized midcentury-modern cluster. The stunning remodel, much of which the homeowners did themselves, mixes updated architectural details and the latest technology with the rarity of year-round outdoor living—options sure to excite even yesterday’s midcentury architects.

On an ideal evening, you’ll find the Henritzes sitting somewhere in the yard, sipping their favorite Gruet Champagne, entertaining a handful of guests with dinner and an outdoor movie, or warming up by the in-ground firepit, which Tom designed after a trip to Palm Springs. On this night, we’re sitting inside on a Le Corbusier–style couch picked up at a garage sale. But with the glass doors wide open, you feel the breeze, smell the fresh rain sprinkling and drop your jaw on hearing about the staggering three-year overhaul the couple plied on the once-mediocre back space.

They smartened up the house by running Cat 5 and other cables through the walls. They installed a radiant heat system by shoving tubing through steel plates attached to the basement’s ceiling. They dug and trenched the yard to build concrete forms. They demoed everything, gutting the house to post and beam. “It almost ruined our marriage,” Darice said, half jokingly. She laughs, even at the memory of living without a roof or working bathroom during monsoon season. “We did a lot of work ourselves because we didn’t have a plan,” deadpanned Tom, who owns a juice bar and counts this as his third remodel. Well, not a plan on paper. They knew, pretty much, what they wanted after spending years ripping pages from modern home magazines. On move in day, they brought just their dining table, junking the “Pottery Barn special” decor of their first home.

The Henritze house is a modern classic, just like this 1950s neighborhood. Arapahoe Acres helped bring Usonian and International style to the area, thanks to developer Edward B. Hawkins and architects Eugene Sternberg and Joseph G. Dion. Even the site plan was radical, balking at linear streets and back alleys. Diane Wray, author of The Arapahoe Acres Historic District, described it as “unconventional, standing in stark contrast to the surrounding neighborhoods,” in her successful submission to the National Register of Historic Places.

The house, known as the Sitterman House for its first occupant, was architecturally startling even in this modern enclave. Designed by Hawkins, the geometric home has strong horizontal lines and international flair. It looks like a rectangular shadow box balanced perfectly on top a smaller base. Its distinctive floor-to-ceiling windows drew the Henritzes to the house a dozen years before Tom spotted the owner pounding a For Sale sign in the rental home’s front yard in 2004.

It’s not that the Henritzes were midcentury modern enthusiasts. They didn’t even know Arapahoe Acres existed when they moved to a house a block away in the early 1990s. But walking their dogs in the historic neighborhood one day, they fell in love. With this one house. “We first saw it around 12 years ago,” Darice said. “We are very patient people.” They quickly got a history lesson.

“Within 24 hours of moving into the house, there were preservationists who were at our door who stopped by to make sure we knew the importance of the house and its historic value. And then there were renovationists who showed up days later to say, ‘Don’t listen to them. Do whatever you want,’” recalled Darice. “There’s a lot of passion in a neighborhood like this.”

They left the house untouched for the first year, living with the dusty shag carpeting, the pink cork ceilings and the mirrors. Oh, those mirrors! Floor-to-ceiling reflective monstrosities from a likely 1980s remodel decorated nearly every wall. “I had to hold my hand out in front of me when I walked through the house to feel where the mirrors were,” Tom joked.

After listening to neighbors and touring similar homes, they nixed the idea to have sliding glass walls and a modern metal railing on the front of the house. “We passed all that up because we realized that the preservation of the facade was really important and we needed to be respectful to what this neighborhood means,” Darice said. “It was important for us to not do that.” Inside, they changed everything. “We did not keep to the concept of midcentury modern inside at all,” Darice said. “We brought it to full modernism.”

That is a big debate in historic neighborhoods. Whether to change or how much to change depends on the situation, says Robert Nauman, who teaches 20th-century art and architectural history at the University of Colorado, Boulder. “Those changes are often practical, given that we don’t live in the midcentury, and even desirable, in terms of issues such as sustainability,” he said, adding, “I would hope that owners of properties in historic districts are sensitive to the overall integrity of the area when they make changes on exteriors or interiors of their homes.”

The Henritzes did get some professional help. They hired several architects to opine about the flow of the remodel and help with permits. And they tapped a unique design source: the local Art Institute. They offered a semester’s tuition to the student with the best ideas. They awarded three scholarships. “One of them had a Mondrian theme for the front of the house and we thought that was kind of cool,” said Darice. It inspired the home’s facade.

Ariel Gelman, a landscape architect, taught the class. Mentored by the fathers of “New American Garden” design, James van Sweden and Wolfgang Oehme, the professor’s simple, natural style appealed to the Henritzes, who hired him as their landscape architect. Gelman translated their desires into distinct, geometric spaces connected by paths, “a journey,” as Darice likes to call them.

There’s a reading room covered by a canvas and wood pergola, the peaceful southern zen den shaded by cherry trees and a moveable dining area and lounging area. There’s also Darice’s vegetable garden (“my spiritual release,” she says) and a few patches of artificial turf for their Golden Retrievers, Emma, Sophie, and Lily. A linear reflective pool flows from the back of the yard underneath the house, echoing the dimensions of the kitchen counter inside. “He (Gelman) really did an amazing job,” Darice said. “He was a very good listener.”

For modern landscapes, the Argentinian native sticks to precise principles: “No curves, no annuals and no fuzzy things,” he said. He relies on hardy grasses and a design focused on minimal watering and maintenance. And when it’s done, he said, “It will look like it was designed when the house was built.” Gelman, a design director at EADG in Asia, is proud of the result but credits his clients for having “good taste and common sense.” The Henritzes did add a few of their own touches, like Tom’s idea to put a gargoyle at the top of the linear pool. “They always surprised me in a good way,” Gelman said.

The major work was left to the professionals, like extending the back of the house and raising the roof. Some materials had to be specially ordered. The floor-to-ceiling glass doors came from Fleetwood Windows & Doors, which shipped them three times from California because they kept breaking. But credit many of the details to the resourceful couple. They planted the 120 grasses themselves. They removed four dumpsters of dirt by hand to lower the backyard six inches so “it looks like the house floats on the landscaping,” said Tom. Trips to their favorite weekend destination, Santa Fe, supplied much of the art. And when they couldn’t find a local seller of Ipe wood for the deck and fence, Tom tracked down an East Coast company that shipped them large pieces, which he cut by hand.

“Would I do it again? Absolutely not,” Darice said with a laugh. “I’m kind of tired too,” Tom responded. “Yes, this is the last one,” she said. “We’re staying here until we die.”