When Elisa Castillo and Rob Solomon bought their East Boothbay property in 2019, the 15-acre parcel had sat on the market for a year. It was densely wooded, covered with scrubby growth, and run through with ledges that threatened to limit buildable lots; roads would have to be built, and electricity and water brought in. But the couple fell under its spell. “It’s a beautiful property with ridges, highs, lows, swamp, everything. We kept hiking through the property, and every time, we saw something totally different,” says Solomon. “It was disorienting. It was magic.” They purchased it and began to plan for a second home that would become a remote work location (Castillo is a psychologist and wellness dean at a public university, and Solomon is a solutions architect for a cybersecurity software company). Veteran travelers, they also wanted to put their Airbnb experience to use designing a home that could be rented when they weren’t using it. A hilltop offered the possibility of an ocean view, and they worked with Kaplan Thompson Architects to design a structure tall enough to see the water while conforming to local height limits. But as they spent more time on the property, they found themselves drawn to a different location: a grove of birch trees surrounding a large maple and spotted with vernal pools. They built a stone firepit there, set some Adirondack chairs around it, and changed their plan.

Putting their custom design on the shelf (for now), they began working with Kaplan Thompson’s sister firm, BrightBuilt Home, to customize a high-performance modular home. Site responsiveness was important to the couple, says Solomon: “I didn’t want a tabula rasa. I didn’t want to take an idea of a house and plop it down anyplace. I wanted to create something shaped around the place.” A modular home is, in fact, brought to the site largely complete, but that doesn’t get in the way of specificity, says architect Jessica Benner, who worked with the couple to modify the firm’s Sidekick model. With an eye toward matching the plans for the hilltop home, they switched the gable form for a shed roof and added clerestory windows under vaulted ceilings. The bedrooms were moved to opposite ends of the module to provide more privacy; the kitchen was converted to a galley. Most high-performance homes are south facing, says Benner, but in this case “the siting of the house has really beautiful views to the east, so we arranged the spaces so that all of that light and sun could come in on the east side.”

Once the design was complete, the home was constructed by KBS Builders in South Paris, while general contractor Mike White of Island Carpentry in Georgetown prepared the site. One of the efficiencies of modular construction is that the foundation can be poured while the walls and roof are being built, rather than in sequence. It can take only two weeks for the home to be constructed in the factory. Then, on “set day,” the home is delivered to the site and positioned by crane, under the supervision of the general contractor, who oversees a team of specialists. At that point, says Benner, 70 or 75 percent of the work is completed. “Once they deliver the module, it takes three months to finish these guys, on average,” says White. “If you build a house from scratch on a foundation, it might be five, six, seven months.” But for White, who has worked with BrightBuilt on around 25 homes, time savings are less important than resource conservation. Several years ago, motivated by the threat of climate change, he committed to building zero-energy homes, which produce all the energy they consume. “It’s the only thing I want to do. It’s the right thing to do, not only for the environment, but also for people’s pocketbooks. It saves money, particularly over a long period,” he says. Because modular construction creates cost savings, it makes zero-energy homes available to more people. “It’s been a mission of BrightBuilt to change the paradigm of modular, bringing high design to the modular industry. It’s meant to make the design and architecture and high performance more accessible,” says Benner.
“I firmly believe that modular is the construction method of the future.”

Finishing the home, for Castillo and Solomon, meant completing its ties to the outdoors. It is a small space—850 square feet—but they never imagined its walls as boundaries. Castillo grew up in Puerto Rico, where, she says, “everyone lives outdoors”; Solomon had a similar experience growing up in a Long Island, New York, beach town and had developed a deep love for the woods while attending summer camp in Maine. They worked with White to add an oversized deck and a separate structure that holds a sauna and outdoor hot tub, while designing a “forest garden” in the birch grove, using stones unearthed during construction. The interior design was “all about elevating natural elements,” says Castillo. They selected light wood trim, clear maple floors, a soapstone countertop, and a fireplace surround made of river stones to anchor the design in nature. Accents in a deep teal were matched to decaying wood they found on the property, which was stained by the green elfcup fungus. Castillo chose artworks that use elemental shapes—circles, squares, and rectangles—in playful ways, to create a calming effect. She hung round mirrors opposite the large windows to bring the forest into the interior and echo the moon motif that appears throughout the home.

The property, which carries the name Forest Spa Maine on Airbnb, was always intended as a retreat, but as construction proceeded during the COVID pandemic, it gained new meanings. By then, the couple had moved beyond camping out on the site: they had built a large platform topped by a Garden Igloo plastic dome tent, and they had also brought in a portable toilet and two-burner gas grill. “We came here every other weekend through that first summer of COVID,” Solomon recalls. “It helped preserve our sanity.” Castillo was heading up the COVID response at her university. “It was so intense,” she says. “We became very mindful of how hungry we are for retreat, escape, relaxation, and wellness. We wanted to create a space not just for us but for others to unplug, be with nature, go hiking, have that meditative experience that could be so healing.” Now that they have a space for themselves and for Airbnb guests, the couple is imagining next steps. They are planning their “third bedroom”—a small, off-grid structure that will expand the home’s capacity for guests. Perhaps they will take that model further, creating private areas for “glamping” around the property; perhaps they will create a wellness retreat. And there’s still that plan for the house on the hill. For now, Castillo says, they are deeply appreciating what they have built. “My favorite thing here is being in the hot tub, when you can see the Milky Way at night. It’s a small house, but you have access to the universe.”