Stella Betts and David Leven have been partners in design and life for almost 20 years, and one of their most recent projects has brought them back to the earliest days of their practice. Named for its straightforward geometry, the Square House—a concrete guest cottage and spa—was methodically cast in place just behind the architects’ very first ground-up residence.

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The duo established their firm, LevenBetts, in New York in 1999 and built a spec house in the Hudson Valley four years later. It piqued the interest of their friend Andrew Zuckerman, a photographer who had visited the site on a whim to shoot the freshly poured slab. Today, those photos hang in the living room of the home, which Zuckerman and his wife purchased as a weekend retreat—and used as the locale for their wedding. More than a decade (and three children) later, the couple reenlisted LevenBetts to design a relaxing backyard getaway for their guests—and themselves. Hiding a varied section and program within a simple plan, the one-bedroom structure is inspired by traditional Japanese inns, or ryokan.

“The project was conceptualized around the idea of bathing and observing nature,” says Leven. A steam room, jacuzzi, and Japanese soaking tub, all made of hinoki wood—a rot-resistant variety of cypress native to Japan—comprise roughly one-quarter of the 1,600-square-foot structure. Operable skylights bring diffuse light to the space, which contains a small atrium with a ficus tree and looks out on a landscaped moss garden.

To further connect inside and out, the architects used oak harvested from the woody site to build cabinetry, and added oversized glazed openings—all of which can be recessed into wall pockets—to each side of the house. They also made many of the building’s amenities accessible from the exterior: the structure’s signature concrete stair leads to a roof garden, which serves as both an open-air living room and an elevated campsite for the kids; the modest bathroom opens to the yard through a narrow, retractable frosted door; and a large outdoor sink, which seems to extend through the glass as an offshoot of the kitchen counter, provides a place to wash up. With all the glazed doors retracted, the Square House becomes more pavilion than building. “We wanted the design to highlight how small the house could be but how big it could feel,” says Betts.

To that end, interior spaces were also created to serve multiple purposes. In the sunken den, a sofa designed by the architects becomes prime real estate for sleepovers, and for movie watching when a retractable screen is lowered, while a studio, with discreet doors and a Murphy bed, quickly transforms into a second bedroom.

In both form and material palette, the guesthouse, firmly rooted in the earth, stands in stark contrast to the wood-clad original. “They have two different ways of responding to the landscape,” says Betts. Where the main building adjusts to the land externally, perching and cantilevering on the sloped site, the Square House negotiates changes in topography internally, incorporating steps and drops within its section.

The architects chose cast-in-place concrete for its monumentality and texture, working with an expert contractor to build elaborate formwork that left notable striations from roughhewn boards on long faces, but smooth surfaces on doorways and entries. “It took more than a dozen pours,” says Betts. “It was a puzzle, but it was amazing.”



508 West 26th Street, 317
New York NY 10001


Personnel in architect's firm who should receive special credit:

David Leven, AIA
Stella Betts, Associate AIA
Andrew Feuerstein, RA
Seung Teak Lee



Structural engineer: Silman (Nat Oppenheimer)


Landscape: Marc Peter Keane


General contractor:

Eric Glasser & Company, Inc



Naho Kubota




Structural System

Cast-in-place Concrete

Exterior Cladding

Masonry: Cast in Place Concrete

Metal/glass curtain wall: Butt Glazed Panels with Fleetwood Swing Doors; Western Sliding Doors
Wood: Oak Cabinetry at Kitchen and Storage Areas. The oak was harvested from the land. Hinoki at bath area.


Built-up roofing: EPDM


Skylights: Lynbrook Skylights


Metal doors: Fleetwood Swing Doors

Sliding doors: Western Sliding Doors


Locksets: FSB

Interior Finishes

Cabinetwork and custom woodwork: Oak Cabinetry at Kitchen and Storage Areas. The oak was harvested from the land. Hinoki at bath area.
Resilient flooring: Concrete Floor

Special interior finishes unique to this project: Cast in place concrete at select walls and Fireplace. Custom concrete counter at kitchen (indoors and exterior) by Art and Construction. Custom Concrete Walls by Art in Construction


Fixed seating: Custom Built-in Sunken Sofa

Upholstery: Maharam upholstery and central living area sofa


Downlights: Lucifer

Tasklighting: Matter

Exterior: BEGA


Custom Concrete Sinks by Art in Construction