The trip from garage to first floor is through a wood-clad spiral staircase that resembles a giant slatted barrel.

The sculptural staircase is a centerpiece of the open-plan kitchen and living room.

A sculptural white steel spiral staircase with wooden treads connects the two levels.

Yeo descends the spiral staircase that connects the public and private spaces while Ian relaxes on a pair of Cappellini Superlight 750 sofas designed by Barber Osgerby. The Gwapa lounge chair and ottoman in the corner were designed by Marcel Wanders.

A steel spiral staircase efficiently links all three floors. With no interior doors, Yurika can keep an ear on the shop from upstairs while maintaining the privacy of her home with the help of the vertical distance.

“The intimate courtyard, with a concrete floor and plants, is an homage to many charming places in Southern California, where my wife and I lived for four years before getting married," says Priatman.

Masahiro and Mao Harada of Mount Fuji Architects Studio wanted to break with the traditional definition of a house when they designed this small Tokyo home. They achieved their goal by using the same material for the ceiling, the walls, and the floor, creating a space that flows beautifully. Photo by Ryota Atarashi.

The decidedly industrial exterior features smooth dark gray stucco, a custom steel mesh wall, and a metal spiral staircase leading from the ground floor to the roof deck. The clients love the industrial look because it feels raw and natural to them. The footprint of the new addition lies at the rear of the existing home, and the dark exterior helps seamlessly integrate the new structure into the natural slope of the land. According to architect John Klopf, the new addition acts as a spatial backdrop for the existing structure, “receding visually out of respect for the original home.”

Resident Peter Østergaard (with Maja, 6, and Carl, 20 months) and architect and photographer Jonas Bjerre-Poulsen have been best friends since they were 13, which makes for easy collaboration. Says Bjerre-Poulsen: “There are always a lot of challenges in a renovation, but Peter and Åsa trusted my judgment and gave me a completely free hand. Usually it’s hard to push people into unconventional solutions, but Peter has all these wild and crazy ideas.” One such idea was to embed a transparent glass-and-iron door in the floor, operated by a hydraulic pump, which allows access to the subterranean wine cellar. At night, the lit-up cellar glows, lending the compact living room an increased sense of verticality.

Ran and her brother, Gen, read on one of the structure’s 44 continuous steps.

Steel allowed Kunding to be playful with the staircase’s form.

A view of the kitchen, with a glimpse of the spiral staircase in the background.

The staircases are built with no central support, giving more focus to their curved form.

Emilie Bédard and Maria Rosa Di Ioia of EM Architecture gave Erik Rydingsvärd’s top-floor apartment in a Montreal triplex a subdued, modern look that evokes his native Denmark. The range hood and satin-finished teak cabinets are by Kastella. The floors are Douglas fir and the walls are spruce, painted white.

"Circle-round | Road"

A sweeping spiral staircase occupies the center of the self-supporting dome. Its reclaimed pine treads echo the dome’s ceiling and contrast pleasantly with the raw steel railing. PAK LED lights installed in the floor add an extra touch of drama to the home’s showpiece.

An unadorned spruce wood staircase leads to the upper level.

Kate’s father predicted they would never use the crow’s nest–like tower, which is reached by climbing a narrow staircase.

Large clerestory windows face the street at the Higashibatas’ house in Tokyo, optimizing both privacy and natural light within.

Shibata made the 10-person dining table using $130 sawhorse legs from Maruki Wood Products Company topped with a sheet of birch plywood. A hole in the sliding wall fits over the table, enabling it to be used in both the library and the meeting room. malki.jp A movable wall clad in wainscoting on one side slides along tracks in the dining-room ceiling, dividing the room into a meeting space and a library. The Shiro Simple Modern Pendant lights can be easily removed and reattached after moving the wall. vanilladesign.jp

Di Ioia and Bédard designed the wrought-iron spiral staircase that leads to the rooftop terrace and sauna as a visual nod to Montreal’s signature outdoor stairways.

All models feature wood treads with thin trim that is made to be nearly invisible.

The stairs can be made to span multiple levels, and are highly customizable in terms of material choice.

In his studio, Priatman blew up an aerial photograph of Surabaya, where he is based, to map his current architectural projects.

The house is surrounded by buildings on all sides except its south facade, which faces the street. An expansive operable window is key for effective ventilation during hot summer months. Additionally, a cantilevered balcony shelters a carport, bike storage, and even a playful swing.

The wall beneath the stairs holds hidden storage, including an Enomatic wine dispenser and Sub-Zero refrigerated drawers.

Bookshelves add extra utility to the undulating staircase in Tokyo's 921-square-foot Coil house. The space was designed by architect Akihisa Hirata for Sakura and Ryo Sugiura, a young couple with two children.

The staircase leads to the living area upstairs.

The top of the house is dedicated to a dining area and a kitchen outfitted with steel-topped cabinets from Sanwa Company.

Three-year-old Ran Sugiura peers out the front door of her Tokyo home, a concept-driven yet surprisingly livable piece of architecture that her parents describe as uniquely well suited to the family’s flexible “futon lifestyle."

For the kitchen, architect Ivan Priatman selected an oven, hood, and cooktop from Teka and a Samsung refrigerator. While the table is his own design, the bar stools and chairs are from Informa.

The stairs lead to a sleeping loft outfitted with a mechanical skylight.

Six staircases, many open to outside light, serve as pathways between the private interior spaces.

"We composed the house to have its highest, brightest space in the middle," says Paul Raff. Warm wood stairs lead to the second floor, which houses guest bedrooms, bath, and a kitchenette for the family's frequent visitors.

The upper level of the 5,300-square-foot space is accessed via a slender stair with reclaimed-wood treads.

A staircase forms the core of the 1,800-square-foot home, with a symmetrical alcove on either side. The steps, hardwood floors, and slatted bridge on the second floor are made of white oak, providing a rich contrast with its white walls.