When Daniel and Jane Solomon moved into his family’s house in the Forest Hills neighborhood of Northwest Washington in 2001, it was supposed to be temporary.

“I wasn’t keen on living there” Jane said.

They had been living in a townhouse on Q Street NW. But with the impending birth of their twin sons, they realized that all those stairs weren’t ideal.

“The plan was, we were going to live in my grandparents’ house, at least for a little while, because it was all one level,” Daniel said. “One of the few things that got done right was that I wasn’t going to force my wife to live in the house I grew up in.”

Distinguished homes for sale in the D.C. region

Forest Hills estate | The 1956 houses were built by Nehemiah Meir “N.M.” Cohen, an ordained rabbi who founded Giant Food with Samuel Lehrman in 1935. The two houses on 1.25 acres are listed together at just under $7.3 million. (Connie Gauthier)

Daniel was raised in the house next door to his grandparents’ house, both of which his grandfather Nehemiah Meir “N.M.” Cohen built. Cohen, an ordained rabbi, founded Giant Food with Samuel Lehrman in 1935.

Before World War II, racially restrictive covenants excluded Jews from living in some D.C. neighborhoods. Because it lacked such covenants, Forest Hills became a predominantly Jewish neighborhood during the 1940s and 1950s. It is here that Cohen built two houses, side by side, one for him and his wife, the other for his daughter Lillian and her husband, Lawrence Solomon, Daniel’s parents.

Although similarly constructed in 1956, the houses were not twins. One had a white painted-brick exterior; the other had a stone exterior.

What finally persuaded Jane to stay was the gardens, a lush landscape that had been designed by Jane MacLeish in the mid-1980s.

“The deal was we’d stay, but we’d do a major renovation,” Daniel said.

Instead of first looking for an architect to redo the house, they began by hiring a landscape architect in 2002 to re-envision the grounds as an English garden.

“We had this marvelous garden in the back, but it didn’t relate to the house,” Jane said.

Landscape architect Richard Arentz created a woodland oasis with winding paths, terraces, more than 100 species of plants, an expansive lawn, a fountain, a gazebo and a swimming pool. The grounds have a natural, organic look.

“What was very important to us was [for] it to be understated, unassuming,” Jane said. “We don’t like grand things.”

Arentz recommended architect Richard Williams to redesign the houses. The Solomons considered and rejected several of Williams’s ideas, from taking one of the houses down to expanding the grandparents’ house to trying to connect the two houses.

“It took a long, long time to sort through it because it was not clear what was the right way to go,” Daniel said.

Then one morning, the phone rang. It was Jane’s mom.

“She had woken up at 4 a.m. and was just ruminating, and she figured out this whole concept,” Jane said. “So I then walked Daniel through it, and we both said, ‘Gee, that makes a lot of sense.’ ”

At their next meeting with Williams, the Solomons shared Jane’s mom’s idea to turn the two houses into a main house and a guesthouse.

“Bless Richard Williams for being a big enough person and confident enough to say that’s good,” Daniel said.

The result is a cozy, cottage-like main house rather than a formal, stately home but with plenty of grand spaces for entertaining and a guesthouse that can function as an event space.

The Solomons said they care deeply about the environment and wanted to incorporate environmentally friendly building practices in the renovation. They persuaded their builder, Peterson and Collins, to deconstruct the two houses, saving everything that could be saved and donating it to Community Forklift, a nonprofit reuse center for home-improvement supplies. Jane chairs its board.

They used reclaimed European tiles for the floors and repurposed wine-storage racks from former Washington steakhouse Blackie’s House of Beef.

“Everything has a little more character when it has a story behind it,” Jane said.

They drilled six 400-foot geothermal wells to help heat and cool the houses and a well to supply water for the garden. They buried two 2,500-gallon concrete tanks in the backyard to store water from the well. Their property and the Rockefeller estate are believed to be the only two in the city with private wells.

“It’s thousands and thousands and thousands of dollars a year if you are paying city water to water a garden that size,” Daniel said.

They added solar coils to the garage roof to heat the pool in the summer and warm the driveway in the winter to prevent snow and ice from accumulating.

It took two years of planning and nearly five years of construction before the Solomons moved into their house. And now, with their sons grown, they are moving.

“I think about it a lot,” Daniel said of leaving his childhood home. “It’s been a hard process at times. But mostly, it was the right house at the right time, and we’re ready to move on.”

The two houses are on the market for the first time. The 1.25-acre property has a five-bedroom, five-bathroom, 5,790-square-foot main house and a three-bedroom, six-bathroom, 5,115-square-foot guesthouse. It also has a two-car garage, a greenhouse, a gazebo and a swimming pool. It is listed at just under $7.3 million.

Listing agents: Christopher Ritzert and Christie Weiss, TTR Sotheby’s International Realty