In the past few decades, the only way to spiff up an antique captain’s house was to sell it to a millionaire and have the buyer’s workmen attack it with pick-axes and bulldozers. But something very different and refreshing is happening to the 1840 Captain Thomas Mellen house on Main street, Edgartown, designed by master builder Ariel Norton, and owned by the Keniston family for the past 80 years. The 2,900 square foot home is now being developed to benefit Habitat for Humanity, and its restoration, conceived as a showcase for Island designers, is beginning to take on fairy-tale qualities.

Captain Mellen’s father, Archibald Mellen, may represent the only American pioneer to head east in a covered wagon. He began in Vermont, and whether his compass was off or he was curiously disoriented, at the point that most sojourners might have found themselves on the banks of the Missouri, Mr. Mellen arrived at the shoreline facing Martha’s Vineyard. He abandoned his rig, sailed across the Sound and established the Mellen dynasty on the Island.

Son Thomas became one of the famous whaling captains of his era, having taken command of such legendary ships as Thrasher, Lucretia and Europa. During the Civil War, in 1862, Capt. Mellen helmed the Levi Starbuck. Five days out and 500 miles from the Atlantic coast, he and his crew were set upon by the notorious Confederate raider, Alabama. A shot was fired across the bow (yes, that actually happened; it’s not just an overused contemporary metaphor). A second shot was fired, the ships drew close together, and an officer from the Alabama ordered Capt. Mellen to strike his flying ensign. The captain refused, a skirmish developed, the Levi Starbuck was captured, ransacked, torched and the leader held captive on the raider for 18 days. Such was the mettle of this Vineyard whaling man.

Capt. and Mrs. Mellen’s son, Archibald, married Eva and eventually the home at the corner of Pease’s Point Way and Main street passed into the hands of the Keniston family.

Now Habitat volunteer Barbara Welsh reveals in a press release, “The idea of a decorator show house had been in the back of my mind for years but when the economy was strong, it was never possible to think that someone would ever give us a house to use. But the market changed and I was friends with the family of the Keniston estate and, with my association with Habitat for Humanity, those pieces of information all came together and clicked.”

Habitat’s board of directors, the Keniston estate, and a host of businesses have donated time and resources. Says Ms. Welsh, “This is an economic stimulus project for the entire Island.”

The first crucial task was for the Vineyard House Painting Services to strip all the old wallpaper, replace the ceilings, patch and prime the walls, and sand and refinish the floorboards on the first floors and the staircase. Outdoors, the surrounding yard of hard-packed sod has yielded to the landscape blandishments of Caleb Nicholson of Contemporary Landscapes, landscape architect Kristen Reimann, and Barbara Lampson of Land Design, all of these jeweled settings overseen by Susan Feller of Susan Feller Design, a Habitat board member.

Days before the show house opens to the public, the designers have transformed their designated rooms with the following features:

Downstairs hallways and the living room were decorated by John Murphy in whites and grays, with grey and white-checked textiles, and paintings chosen by art dealer Holly Alaimo, who will also be overseeing the boutique (put together by Annie Parr of Island Interiors), a retail space packed with arts, crafts and other home items. Mr. Murphy also refinished the back stairway and applied an ethereal pink paint to the treads that glows with greater intensity as the steps climb towards the windows.

The front sitting room was decked out by designer Mary Rentschler with autumn leaf wallpaper, rustic furnishings and a continuous high white shelf adorned with multi-colored antique bottles. Bev Fearey and Jane Norton of Past & Presents transformed the dining room with a classic English cherry-wood table and chair ensemble, and a hand-painted bureau topped with a circle-head mirror with lacy wrought iron trim. The rear study, designed by Kathryn Tate, picks up more of the household’s cream, tan and green hues with an antique desk and chairs for moments of leisure.

The kitchen, a collaboration of Kevin Cusack and Rock Pond, houses a central table, glassed-in white cabinets and a wide-planked wood floor.

The front spiral staircase is another masterpiece from the paintbrush of Margot Datz: ascending faux mosaic blocks featuring the various virtues such as optimism, humor and faith. The upstairs front bedroom displays Lorraine Parish’s celebrated pen-and-ink, white-and-blue nautical linens, an elegant wing chair, and pale brown walls with a white chair rail. Directly across the hall, Martha’s Vineyard Tile resurrected the bathroom in various jazzy patterns of black and white tiles; as a final witty touch, an ankle-length black satin slip hangs on the door.

The central sitting room, done by Nancy Kelly of Bradford Designs, is painted a gleaming blue. A U-shaped bank of ivory sofas holds a jumble of pillows, and the walls are graced with harmonizing paintings, and a school of ceramic turquoise dolphins.

Paula Conover made over a small space into a delectable baby’s room, with a poppy-pink wall, a porcelain and brass crib decked with black and white toile linens, and an antique white rocking chair. The large back bedroom, renovated by Rosemary Casey, features pale mint green walls, a brass and iron antique bed swamped by white and green linens and a romantic sweep of white curtain swags.

Proceeds for Habitat for Humanity will come from items offered for sale in all the designers’ rooms, and from viewing fees. The show house opens on June 28 with a patron’s party the evening before. Advance tickets of $20, or $25 at the door, $20 for seniors.

Opens to the public on Sunday, through Oct. 12. Hours: Tuesday, Wednesday, Friday and Saturday from 10 a.m. to 4 p.m., Thursday 10 a.m. to 7 p.m. and Sunday noon to 4 p.m. Details online at marthasvineyardshowhouse.com.