Japanese design studio Nendo has used giant functional stairway passing through the facade of this two-family house in Tokyo, Japan. 

Named Stairway House, a "stairway-like" structure is used to avoid the two households being completely separated at the top and bottom, which was designed in the south yard. 

The stairway continues upward into the building and penetrating the first through third floors.

The house is located in a quiet residential area of Tokyo. With other houses and apartment buildings pressing around the site, Nendo pushed architectural volume to the north to take in daylight, ventilation, and greenery of the yard into the living environment by using a large glass front southern façade. 

The layout plan made it possible to preserve the existing persimmon tree beloved by the previous generations. The studio considered the potential difficulties of going up and down the stairs for the older couple, so the rooms were arranged on the first floor. 

"The eight cats living with the older couple roam in and outdoors more freely, and encourages the mother to enjoy her hobby of gardening more freely," said Nendo. 

"The younger couple and their child reside on the 2nd and 3rd floors," added the office.  

The stairway is enclosed and features functional elements, such as bathrooms and a staircase for actual use, with the upper part taking on the look of a semi-outdoor greenhouse with abundant greenery as well as a sun-soaked perch for the cats to enjoy climbing. 

And so, a stairway and greenery gently connected the upper and lower floors along a diagonal line, creating a space where all three generations could take comfort in each other’s subtle presence. 

"Not only does the stairway connect the interior to the yard, or bond one household to another, this structure aims to expand further out to join the environs and the city —connecting the road that extends southward on the ground level, and out into skylight through the toplight," added the studio.

Site plan 

Ground floor plan

First floor plan

Second floor plan

Section

All images © Daici Ano and Takumi Ota

> via Nendo