A massive faux concrete staircase cuts the facade and runs through the floors of the aptly named Stairway House in Tokyo, conceived by Japanese design studio Nendo. The intervention has been aimed to unite the family members of three generations - an elderly couple with their eight cats and a younger couple with a child - residing within the house.

Located in a quiet residential neighbourhood, the site earlier inhabited a small wooden property, which was largely overshadowed by the adjoining apartment buildings. Nendo approached the project by pushing the architectural volume to the site’s north, leaving a large yard space to the south that opens onto the street. The design also preserved a large persimmon tree that stood on the site as a gift from its previous dwellers.

The layout has been designed to provide ease of circulation as well as the desired privacy for each member. The first floor has been taken up by the elderly and their cats - the mother who is fond of gardening can easily access the backyard while her cats can lounge on the sun-soaked steps of the stairway. The second and third floor with ample space for work and living are for the younger couple and their kid.

While the front façade of the building has no fenestrations, the rear is punctured by vertical glazed panels and a sculpturesque staircase that brings fresh air, greenery and abundant sunlight into the interiors. Several potted plants dot the flight of concrete steps, creating a semi-outdoor green house for the family. The large steps surrounded by the indoor greenery create ‘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," mentions a statement by Nendo.

Besides connecting the family at every level of the house, the stairway encloses a steel structure on its inside, which consists of bathrooms, a room for cats and an utilitarian staircase for people to internally access the floors.

The interiors are stark, and designed with minimal furnishing. While the walls and cabinetry are kept white, the furniture in contrast is all black. Dark wooden flooring consistent throughout the house injects some warmth to the otherwise visually cool spaces. Openable glazed panels at the rear façade allow adequate ventilation within the house and keep the interiors comfortable and airy.

The multi-generational stairway house, with its many pockets of solitude as well generous spaces of unity, makes it a home where people, animals and nature share space and become one.