tomomi kito architects & associates has completed the interior renovation of an existing two-story timber-made house in tokyo, built approximately forty years ago. the client is a young couple who decided to live with the wife’s parents in that very same house. soon after, the wife’s grandmother was also invited to stay with them. as such, they requested a design suitable for accommodating four different generations – the grandmother (1st generation), the parents (2nd generation), the couple (3rd generation) and their son (4th generation).

first floor common space – looking towards the entrance
all images © satoshi shigeta



while the daily behavior patterns of the each family member is different, creating a space to promote connection between all generations became a major focus to tomomi kito and his team. moreover, the existing rooms were split into smaller functions and as such, they were not open to the outdoors nor to each other, offering poor daylight and no natural ventilation. with these issues in mind, it was decided to improve the quality of the space, as well as daylighting and ventilation. 

second floor common space – catenary shaped ceiling gently covers the room



first, the arrangement of the private rooms were carefully studied to take full advantage of existing windows – thus maximizing natural daylight and ventilation. the remaining spaces were designated as ‘shared’ ones that were open to all family members and planned in each floor with utilities. the private rooms are also exchangeable so as to enhance communication between generations – similar to a shared-house lifestyle. the nature of the shared spaces was consciously enhanced by linking them to the outside and entrance space.

the all-wood design creates a seamless link between different areas



at the same time, the team also assessed the existing structure. although the columns were densely arranged in accordance with the existing partitions, the existing house was structurally unbalanced and lacked the necessary physical resistance. as such, reinforcements  were added through supporting beams and plywood whilst optimizing the use of its existing structural components. thanks to those studies, some columns were deemed redundant and thus removable, providing an opportunity to create larger open spaces.

second floor kitchen space 



the ceiling of the shared space on the second floor is catenary shaped – enhancing a natural connection to the outside and maximizing the diffusion of the natural lighting. ‘this architectural feature gently envelopes all four generations of families who ultimately enjoy living in a space abundantly airy and lit,’ concludes the studio. 

the metal partition allows natural light to lower floor and accelerate airflow between floors

1st floor entrance filtering in natural lighting 

staircase: upper half steel-made and bottom half timber-made

staircase – seen from 1st floor common space through glass partition

2nd floor common space – supporting beams are installed under the existing ones for structural reinforcement

the 2nd floor private room 

private unit flooded with natural daylight 



designboom has received this project from our ‘DIY submissions‘ feature, where we welcome our readers to submit their own work for publication. see more project submissions from our readers here.


edited by: lea zeitoun | designboom

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