Called Amagansett Beach 3, the family home comprises two gabled wings that are linked by a lower portion whose roofline nestles into their sides.
"The house was designed for a young New York City-based creative family who originally grew up in the Hamptons and South Africa," the studio told Dezeen.
"They wanted something that fit with the vernacular style of the area with a warm and modern interior."
Amagansett Beach 3 also features a combination of woods inside, as well as cream and grey tones to make a uniform palette.
Wood is used on the floor, accent walls, built-in closets and bathroom vanities, and ranges from bleached walnut to live-sawn white oak.
On the ground floor in the main living area, which is in the middle of the home, is an open-plan kitchen, dining room and lounge with ceiling beams sourced from a local barn.
A row of glass doors opens to a patio, where there are lounge chairs and an outdoor swimming pool.
KOS+A designed several custom pieces for the home, including oak kitchen cabinets and pantry storage, a stone dog bath in the mudroom nearby, and a cream sofa in the living room covered in Kravet fabric.
The kitchen island, which is topped with white marble, was custom-made by the studio. It also created the millwork closets in the foyer made from white oak that has been bleached, fumed and whitewashed.
Accents include a Capo Lounge Chair that Chinese studio Neri & Hu designed for De La Espada, a white dining table and black versions of Danish designer Børge Mogensen's Soberg chairs
The heart of the home is flanked by several rooms on either wing.
An office and a television room with an L-shaped sofa are on one side, and on the other are a mudroom, foyer, laundry room, pantry and guest bedroom.
Upstairs are a second home office and three bedrooms, located within either wing of the house. One of them is a kid's bedroom with a circle window overlooking the great room below.
The master bedroom has accesses to a rooftop deck overlooking the pool and backyard.
KOS+A is based in Bridgehampton, New York, and is led by Scottish architect Kevin O'Sullivan and Long Island native Luke Ferran.
Founded eight years ago, the studio specialises in residential projects in the region.
Amagansett one of a number of small towns in Long Island, which is a popular summer destination. Other properties in Amagansett include a farmhouse clad in charred cypress by MB Architecture and a cedar-clad home by Studio Zung.
Project team: Kevin O’Sullivan, Luke Ferran, Dina Abu-Jawdeh, and Kate Wirth
Landscape design: Harmonia Inc
Contactor: Jonathan Wirth, JT Wirth & Co.