Chiasmus Partners Wraps a Concrete Crescent House Around a Hillside Lawn in Yongin

Hyangrindongsan, in Yongin's Dongbaek-dong, is the kind of Korean suburb where detached houses settle into forested slopes one terrace at a time. Retaining walls, trees and changes in level overlap so that every garden borrows a little of its neighbour's view. Into this layered hillside, Chiasmus Partners, the atelier founded in New York and now working from Beijing and Seoul, has set The Orb House: a 198 m² home whose white, curving body bends around a lawn rather than sitting on top of it.

What interests us is not the curve itself. Plenty of houses use curves as a signature. Here the curve does real work: it turns a mid-slope plot, exposed to the village below and the houses around it, into a protected interior landscape while still keeping the long view open. The crescent is a privacy device, a sun catcher and a circulation diagram at the same time, and the interior carries the same geometry all the way down to the stair and the openings in the floor.

A Crescent Among Pitched Roofs

From above, the strategy is clear. The neighbours read as conventional boxes with metal and tile roofs, each turned to face the slope. The Orb House instead draws a continuous white arc that cups a grass courtyard, with a lobed roof extending to shelter a paved dining terrace beside a cypress hedge.

The roof is effectively the fifth facade, and on a hillside where you look down on your neighbours' houses, that matters. The house gives back a calm, legible figure to the people above it while keeping its own garden screened from the street and the adjacent plots.

A Glass Edge Facing Inward

The courtyard side is almost entirely glass, held between thin white bands that read as roof edge and floor slab. Because the glazing follows the arc, no single pane faces the lawn head-on; you always see the garden at a slight angle, and the curve keeps pulling your eye toward the wooded hills beyond.

The lawn is not flat. It slopes, is crossed by stepping stones, and drops into a sunken terrace held by a white retaining wall. That is a direct reading of the neighbourhood's language of terraces and walls, folded inside the house's own boundary instead of left as leftover space between buildings.

Courtyards Cut Into the Slope

The most intimate exterior space is the sunken courtyard, planted with hostas and ferns and opened to the sky through the roof. It works like a light well at garden scale: shaded, damp enough for woodland planting, and visually connected to the rooms around it.

Concrete steps run beside a round column and climb between curved white walls and a black railing. These exterior stairs are handled plainly, which is the right call. They let the topography do the talking and give you a sequence of small level changes rather than one heroic stair.

A Reserved Street Face

From the road, the house shows very little: a rounded white upper volume over a dark garage door and a planter of conifers. It is a deliberately quiet front, closer in attitude to a courtyard house than a suburban villa.

The entry hall continues that restraint. An oak drawer unit, a long mirror and a curved wall meet a concrete column and a tall window. You get a compressed, controlled threshold before the plan opens up to the garden.

The Stair as the House's Spine

The sculptural white spiral stair is the interior's centre of gravity. With wide concrete treads and a smooth white plaster body, it rises from the kitchen and dining zone toward an upper lounge, repeating the crescent of the plan in vertical form.

What makes it convincing is how close it sits to everyday life. The long timber dining table runs right in front of it, a fig tree sits by the landing, and the underside of the stair becomes a ceiling for meals. Seen from above, through a curved opening, the dining area reads as a room within a room. The stair is not a gallery object; it is furniture at the scale of the house.

Concrete Columns, Sheer Curtains, Polished Floors

Against all that smooth white, the round board-formed concrete columns are the honest counterweight. They stand free of the curved glass, so the facade can stay thin and continuous while the structure shows up inside as a rhythm of solid points beside sofas, palms and tables.

Sheer curtains soften the glazing and give the occupants a way to manage exposure without breaking the curve. Sunlight throws window shadows across the polished concrete floor, and an oval opening overhead, with its looping plaster edge, pulls daylight down from above. The palette is limited to concrete, white and timber, and that limit is what keeps the geometry readable.

Sleeping Along the Curve

Upstairs, the bedrooms keep the open logic of the ground floor. An open sleeping area sits behind a curved parapet, a column marks the edge of each space, and one bedroom rises into a vaulted ceiling. The hills stay in view through the glass.

The trade-off is privacy. Parts of the upper level read more like a mezzanine than a set of closed rooms, which suits a household comfortable with openness and relies heavily on curtains elsewhere. It is a clear position, and we would rather see a house commit to one than hedge.

Why This Project Matters

Suburban hillside sites in Korea and elsewhere tend to produce houses that face the view and turn their backs on everything else, leaving awkward side yards and exposed gardens. The Orb House shows another option: draw the boundary as a curve, make the garden the room the house is built around, and let the retaining walls and level changes of the neighbourhood become part of the interior landscape.

It also shows that formal ambition and domestic ease can coexist. The crescent, the spiral stair and the oval openings are strong gestures, but they are carried by plain means: concrete columns, glass, white surfaces and a disciplined material palette. For architects working on modest 200 m² houses, that is the lesson worth keeping: one geometric idea, followed through consistently, can organise site, structure and daily life at once.

The Orb House by Chiasmus Partners, Yongin-si, South Korea. Area: 198 m². Completed: 2023. Photography: Namsun Lee.

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