Some people make houses out of molds.

The sofa goes here, because House & Garden said so. The carpet’s just like the one we admired at John and Jean’s, next door. And the curtains, well, Mother always said solids, not florals.

Other people watch their houses grow. Like precocious children coming into their own, or dandelions staging a quiet takeover. They choose a decor because they like driftwood and Art Deco lampshades and broad wooden floorboards and fieldstone.

At Phil and Priscilla Barter’s home on rural Hog Bay Road in Franklin, a colorful sign outside bears a single word: “Art.” It refers to the attached galleries that show off the family’s talents, but it could also describe the house itself.

The Barters have lived here, in the woods of Hancock County, since they married in the early 1970s. They have added onto the structure every year, and that centered swirl of half-random outgrowths, together with their visual flair and textured collection of objects, creates the rough equivalent of a live-in sculpture.

“I grew up living in parsonages, where we had to keep everything neat,” said Priscilla Barter. “My happiest time was at our summer camp, an old schoolhouse in Madrid [Maine]. Being in Phil’s house was like being back in camp again.”

Phil’s house was born of a sign on the road in Northeast Harbor. “Free Garage,” it said. Barter, a resourceful Maine native who had just returned to the state after several hippie years in California, recognized a rent-free way to stay warm.

The garage had no roof and was too big to fit on his truck. Barter took a chain saw and split it down the middle. On the Sullivan-Franklin line, he traded his truck for the land to put his new house on.

“I built a roof and moved in right away,” recalled the artist, at home by the stove in his trademark black hat, a turquoise ring on his finger.

Trying to trace the evolution of the Barter homestead is like searching world genetics for the origins of man. Windows have been moved, walls have been knocked out. Porches turned into kitchens, spaces once boxed in popped out.

The Barters didn’t have much money starting out, and they didn’t borrow. The posts that hold up the roof and the beams that cross the ceiling are worn and weathered driftwood, salvaged from the beach.

“When we started to add on, I said I wanted it always to feel the same way,” said Priscilla Barter. “I wanted the same campy, on-vacation feeling.”

The house progressed at about the same pace as Phil’s reputation as an artist, its add-ons corresponding to stylistic mutations and sales of paintings. When a client invested in a houseful of Barter art, they added one gallery, then another. The births of seven children filled the new spaces as fast as they were built.

They built a shingled sauna in the back yard, and a two-story studio for Phil a short walk from the house, near the sheared-off tree he carved and painted to look like Abe Lincoln. He keeps his art library on the top floor.

Until there were six children, the house had no running water.

The oldest Barter offspring is now 32. The youngest, Jack, is 16. Lucky visitors to the gallery will find him there playing the piano. Seven of his original compositions were recorded this month for a debut compact disc.

Now that all six of Jack’s siblings are married, another expansion is under way, so the whole family will be able to sit around a table together when they gather at the homestead. They could have hired someone, but opted to do it themselves, to keep consistent the slightly offbeat lines of the structure.

These days, any construction prompts a chorus of questions.

“The kids worry we’re not going to keep it the same,” Priscilla Barter said.

It’s not that the house seems particularly unique to them, having grown up there. Sure, their friends always loved to come over, but “it’s reality,” Jack says with a shrug when a visitor enthuses about the environment.

They may be protective because their whole family history is written — sometimes literally — on the walls. Upstairs, the slanted ceiling in one bedroom bears a child’s drawing of what looks like a truck. Across the hall, another brother painted a carpet of green grass and red flowers on the wood floor.

“All the kids who ever came here said they loved the feeling of it,” said Priscilla.

The walls bear the intimate patterns of years of busy living, including trails of nail holes from the ever-changing parade of paintings through the house. Current works are by Phil, his son Matthew, and a gifted son-in-law.

“And what’s wrong with nail holes?” Priscilla asks, sincerely. “Nail holes look wonderful.”

In the master bedroom, where a window is kept open year-round for a breeze, driftwood mobiles and tiny airplanes dangle from the ceiling. Antique books line the shelves over low-set windows.

The armoire against one wall is decorated with one of Phil Barter’s cactus woodcuts. The trunk at the foot of the bed, a salvaged grain bin, is painted gray and topped with a woodcut lizard.

The attached bathroom was going to be all white — and was, briefly — until Priscilla spilled a can of gray paint. Today, the floor is a Jackson Pollock tribute of multicolored paint scribbles.

Downstairs, it’s possible to step from island to island on the vibrant ovals of Priscilla’s hand-braided rugs, one of the crafts she sells, along with dolls and hats, in the gallery shop.

The house is dense with treasures. Every object has a story. It’s clear the Barters like their things in jumbled mass quantities, assembled in mysterious junk shop patterns. (It’s not the things themselves that matter — it’s the pleasing chaos of shapes and colors.)

Dozens and dozens of coffee mugs hang from the kitchen beams like Christmas tree ornaments. In Phil’s studio, there’s a stack of carefully labeled drawers: “Things.” “More things.” “Stupid things.” “Stringy things.” “Chisels.”

Up in the beams of the living room, your eye might light on an oar or an old rifle, an animal’s jawbone or a shelf full of porcelain elephants.

Color schemes are mismatched, and utterly invigorating. The dining room floor is mint green; the cabinet doors are sky blue with pink snake zigzags. The living room windows sport curtains in three different floral patterns.

In short, the house is about as much fun as you can have and still stay home.

After all, Priscilla says, “we don’t have to go to work. If someone drives in, we can put the lights on.”