The Deep Dive: A Sculptural Spa Shed

As any issue of Dwell proves, the choice of material or joinery method can transform a good project into a design for the ages. The Deep Dive is a forum where Dwell Pro readers can obsess over those details. Here we ask expert colleagues to share the inspiration behind house elements that delight clients—as well as the nitty-gritty information with which they strategized the solution.

A Soaring Little Structure

In the September/October issue, we head to the Westchester County converted dairy farm home of Chandra and Sharmila Sen, which was recently completed by rising-star design studio Worrell Yeung.

Brooklyn-based architects Max Worrell and Jejon Yeung not only created a compound that is rich with amenities—pool, pond, guesthouse/studio—but also moved regionally-inspired modernism in a new direction. This edition of The Deep Dive takes a closer look at the property’s "spa shed," which encapsulates the architects’ approach to the entire commission. Although its footprint covers a mere 450 square feet including decking, the soaring little structure boasts a resort-like program and architectural ambition.

Occupying the eastern flank of the compound, it is a destination where homeowners Chandra and Sharmila retreat to a sauna and outdoor shower, which center on a slim entrance that recalls the portal-like stairwell of the main residence. The three zones encompass 190 square feet, and they are juxtaposed to an easternmost 110-square-foot mechanical yard whose equipment serves all buildings on site. Together, they form a single half-gable volume that, reaching 18 feet in height, is more abstraction than farmhouse throwback. 

"We thought agrarian forms were compelling, and that by carving a building from the traditional gabled volume, we would achieve an ambiguity that’s in keeping with the compound’s private, residential use today," Yeung says of the spa shed’s more cultural goals. "Because there are no glazed openings except for one window at the sauna, you approach the spa shed without necessarily knowing what it is or that it’s even inhabitable."

Appearances are deceiving in part because the spa shed seems to dematerialize along its west-east course. The pre-weathered cypress surrounding the mechanical yard "is effectively a slatted fence that allows air to flow to the mechanical units while still obscuring them visually," Yeung observes of the 4-inch-wide cypress boards that are separated by inch increments. The slats follow the profile of the shed and, thanks to their limited spacing and towering height, it’s not immediately clear that they have no roof to support. Instead, they reach to the sky.

Meanwhile, the shed’s more enjoyable rooms are enclosed in a meticulously executed five-sided rainscreen that is anything but evanescent. "In early studies, we topped the spa shed in standing-seam aluminum roof to match the main house—but that material choice turned it into a mini-house," Worrell recalls. "By using cypress on the roof and walls, the shed has a more monolithic quality. And using the rainscreen allowed us to wrap the surfaces into one another, to make the shed seem more illegible in terms of its scale." This is the first project in which Worrell Yeung has employed a rainscreen for a roof.

Worrell describes the finishing layers of the roof assembly, in which a rubber membrane and the cypress sandwich two layers of furring: the inner furring runs in the same direction as the siding, so water can drain; the outer furring is rotated 90 degrees. "It was fun pushing the boundaries of the detailing," he adds. "There’s no coping, the zinc flashing is only as deep as the material itself, and, at a distance, the cypress and zinc colors blend well enough to have that monolithic reading we were interested in." Two lightwells in the angled roof reach down to the entry and outdoor shower zones, and Yeung explains that their openness gives the impression that the building envelope is weighty. "Glass skylights would have made the skin seem taut, taking away from our desire to carve the shed out of a gabled block," he adds.

The architects’ approach to the foundation amplifies the spa shed’s artistic quality, and supports the inkling that inhabitable spaces and the mechanical yard are fused. The shed frame was erected atop a deck perched on helical piles that extend down to the frostline. The exterior skin, in turn, kisses the ground—from some perspectives it almost seems that the cypress emerges from the gravel and earth, like a sculpture without a plinth. Besides convincing their contractor to defy convention, which states that natural material should hover several inches above the datum, Worrell and Yeung leveraged gravel pathways as well as the site’s natural slope to prevent excess moisture from degrading the cypress.

Just as the spa shed’s monumental and fleeting halves seem united, they need one another to succeed as a composition. By placing the two programs next to one another, "the volume is more proportionate to the rest of the compound," Yeung says. (The shed sprouts 150 square feet of decking to contain a hot tub and to further elongate its presence.) The rainscreen enclosure achieves some of its gravity, as well, because the more diaphanous mechanical yard places its visual solidity and thickness in relief. And the spa shed boasts an overall mysterious appeal because it intangibly resembles the compound setting, as Worrell says: "Compression and openness isn’t unlike the relationship between meadow and forest. Playing with that duality is something we like to do in a lot of our projects." 

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