The ocean is a hard taskmaster, says landscape architect Chris LaGuardia. And he’s got ample proof in the form of a Sagaponack, N.Y. project he’s been working closely on for the past 12 years – a sculptural oceanfront cottage designed originally by the rustic modernist architect Norman Jaffe in the 1970s.

When the property’s last line of protective dunes washed out to sea in 1998, the cottage faced a similar fate, suddenly laying exposed and at the mercy of the Atlantic. That is, until its owners, working with LaGuardia (an apprentice to Jaffe in the 1980s) and architect Christian Sabellarosa made a bold bid to save it.

“We jacked it up and moved it 300 feet back,” says LaGuardia, principal in the Southampton-based firm bearing his name. “We moved it to a big field – it looked like a giant piece of tumbleweed.”

The clients had been the sole owners of the four-story house, a barn-and-saltbox hybrid clad in gray cedar shingles. Its striking design had earned it coveted Record House status from “Architectural Record” magazine in the mid-1970s, along with a slew of other awards. But by 1998, the owners were not only ready to move it, but also to add a ground-floor master suite.

Once it was settled into its new site – a 600-foot by 2,000-foot piece of open farmland, half of it under cultivation – the question of how to protect it from the Atlantic became top-of-mind. “We needed 30,000 cubic yards of fill to create new lines of dunes,” says LaGuardia.

They could have trucked it all in from elsewhere, but the landscape architects reconsidered. They suggested mining the fill on site by digging down 12 1/2 feet to create a pond. “There were 18 inches of topsoil, three feet of silty, loamy clay, and then pure sand,” he adds. “We excavated it and stockpiled it, and then recast it for the sand dunes.”

The pond, with a waterproof fabric layered at its bottom and 12 inches of sand atop, covers 60,000 square feet, with depths varying from 6 inches to 11 feet.

The clever concept has highly pedigreed precedents. For starters, there’s Capability Brown’s lake at Blenheim Palace in Oxfordshire, England, once home to Sir Winston Churchill. And then there are the water features at the 17th-century Katsura Imperial Villa, in Kyoto, Japan.

In Sagaponack, though, LaGuardia took his design cues from the landscapes of Montauk, where plenty of ponds lie hidden behind ocean dunes. He found further inspiration in the landscape paintings of William Merritt Chase and Andrew Wyeth.

Beyond the artistic influences lay the functional questions of how to build the dunes, how to nestle them up to the cottage, and how to handle the transition from beach to residence to pond. The landscape architect decided first to recreate the original dunes in a series of rank-and-file undulations that graduate up toward the house.

“There’s a primary dune at the oceanfront, and then they’re all laid out in an east-west fashion to echo the ocean waves,” he says. “The native dune line runs in an east-west line from New York City to Montauk and we worked hard to emulate that.”

Working with architect Sabellarosa, LaGuardia integrated the long, linear, 2,500-square-foot addition into the landscape, also along the east-west axis, while the original cottage is once again snugged up against a dune, the pond at its back.

Most of the landscape plantings are self-sustaining and natural, with American beach grass on the ocean side and fescue and little bluestem leeward.

The heavy lifting for the project – making a 15-foot rise of land look like natural topography – kept the landscape architects busy for four years. Since then, they’ve worked on it annually, planting and improving.

“We keep a close eye on it,” says LaGuardia. And their meticulous repositioning of this 1970s gem has paid off in spades: late last year, it earned an Award of Excellence from ASLA, the American Society of Landscape Architects. “It is a great house and a great story,” the awards jury wrote. 

Like the wonderful design of its landscape, that’s a true understatement. For more information on LaGuardia Design, visit laguardiadesign.com