Sagaponack Mansion Mystifies Neighbors

A large-scale residential build is underway at 511 Daniels Lane in Sagaponack that’s turning heads.

Situated on a narrow 18.4 acres, the property’s listed owner, Stem Partners LLC, purchased the vacant land for $38 million in 2011 from Brenda Earl—thought to be the same former Zweig-DiMenna partner who bought the 44-acre Water Mill oceanfront estate created by Henry Ford II called Fordune in 2002 and now listed for $175 million.

The limited liability company is in the care of a financial planning firm called The Ayco Company LP, and is backed by Goldman Sachs, according to New York State records.

In 2015, plans surfaced for what the LLC planned to do with the swath of land. The two-story, 23,665-square-foot manse is nothing to sneeze at, including eight bedrooms, 10 bathrooms, five half baths, a basketball court, a tennis court, a pool, a pool house, a spa and a pavilion. Gena Hatcher, the LLC’s manager, could not be reached for comment about who is moving in on Daniels Lane.

“I have never seen anything like this done before,” Sagaponack Village building inspector John Woudsma said in a recent interview.

He described the manse as a true feat in engineering “nothing like the Hamptons has ever seen.” Mr. Woudsma said everything from how the ground was excavated—like a “gold-mining operation”—to how tons of concrete beams were suspended in enormous tanks of water, which offset the force of moving heavy structures into place, was like “how Manhattan skyscrapers are developed.”

He added, “It’s clear that a real mover and shaker is moving in next door.”

Barbara Slifka has lived a few doors down on Potato Lane, which runs along the waterfront, since 1986. She remembers the days when there weren’t such large homes all over the place.

“They own the entire property from the ocean to the road,” Ms. Slifka said. “They are entitled to build whatever they want to build. Naturally, I always wish they were smaller but it’s not in my face—I am still looking at the ocean and it doesn’t affect me in anyway. It’s too late in the game to complain.”

Lee Schulman has the perfect view of the construction from his south-facing window on Ocean Breeze Lane. For that matter, he used to be able to look across sweeping agricultural preserves straight down to the ocean. But he’s not bitter.

“As long as they are not breaking the law, I am indifferent,” Mr. Schulman said. “No one builds a small house anymore, what can I tell you?”

The spirit of the project from the beginning of the process back in 2015, when the proposal was before the village’s Architectural and Historic Review Board, was to keep with the aesthetic of Sagaponack—where “beach meets the water,” said a person involved with the project who spoke on the condition he not be identified.

Before the mystery family became the property owners, the land was zoned for up to six residential parcels. In doing a single property on a combined lot—albeit, now a much larger estate—there’s more open space. It could have been a cluster of houses like what is seen directly to the east and north of Potato Lane.

The front half of the property is a private agricultural reserve that Mr. Woudsma suspects will be leased as farmland. At the end of the long, winding driveway—past the reserve, the basketball court, the pavilion and the tennis court—the gravel entrance to the two-story mansion is lined with a sculpture garden and peach, plum, pear and apple orchard on a tiered landscape.

The main house is wall-to-wall glass windows peering out over the Atlantic to the south and Sagaponack to the north. As seen in renderings submitted to the village by Leroy Street Studios Architecture, the front door is sunken slightly into the ground. The main floor—made to feel like an open agricultural building—is divided into a half story comprising the kitchen, dining and living room space. The upper level has most of the guest bedrooms. Down the hall and up an elevator to the second floor is the master suite. On the right is an office, exercise room and dressing room. The master bedroom extends the entire length of the house on the left. The master bath connects to both halves, and includes a bathtub nook that looks through a bay window.

From an architectural point of view, having the pool and pool house close to the main house allows for a different kind of connection of outdoor and indoor living spaces that rivals the typical Hamptons shingle-clad home.

The large glass windows “substantially insulate” the home, according to the plans. The home also uses a geothermal system for efficient heating and cooling, the roof has solar panels and the estate has its own generator.

With any luck, when the construction is finished, because of the sweeping agricultural reserve and low-to-the-ground estate, the hope of the homeowner is keep the house “out of sight and out of mind.”

The property was assessed at $57.87 million. It’s in good company—Ira Rennert’s 63-acre eye-popping compound Fairfield is just two doors down.