Two-Family House｜Custom-built homes by architecture firms9Picks｜A Home Where Two Families Coexist Harmoniously

In two-generation residences where parent and child households live under a single roof, the core of the design challenge is how to protect each household’s daily rhythms and privacy while maintaining an appropriate level of connection. Plan typologies vary according to the relationship between households and site constraints — from fully independent units to partially shared arrangements and fully cohabiting layouts. Key issues to address from the design stage include the extent of shared entryways and wet zones, acoustic separation between households, and adaptability to future changes in family composition. Design firms undertake careful interviews to understand the lifestyles and values of both households, and then develop schemes that allow each to be autonomous while naturally supporting one another. We present case studies that respond to the evolving nature of family life.

A two-family courtyard house featuring an inner courtyard and a roof terrace.

This is a two-generation house built along Yūzō Street in Chigasaki. It was planned with the theme of integrating nature and family connections into daily life while providing security and structural robustness. At the center of the residence a courtyard-house configuration is adopted, enclosing a central courtyard. Trees transplanted from the existing garden and a wood deck gently connect the parent household and the child household. Openings placed throughout admit light, breeze, and greenery, achieving an appropriate sense of distance between households while enabling rich communication. The dwelling harmonizes functionality and comfort.

A house set on the eastern foothills of Mount Yamato Katsuragi, crowned by a simple pitched triangular roof. Inhabited by a married couple, the mother, and two cats, the dwelling zones partially overlap to preserve a balanced distance between two-family separation and single-house cohabitation. The couple’s LDK on the ground floor connects to the second-floor landing, bedroom, and wet areas via a double-height stair with large windows and bookshelves. The mother’s program places the bedroom and wet areas on the ground floor and a compact LDK on the second floor. Outside, fields and the seasonal expression of Mount Katsuragi frame a slow-paced atmosphere.

This is a multigenerational renovation of a 40-year-old timber-framed house, planned for the family and mother returning to the home where they were born and raised. While preserving the sound existing structural frame, the minimum necessary structural alterations and seismic reinforcement were carried out to regenerate the dwelling into a living environment appropriate for a new way of life. The garden, which the father had created, was carefully retained, and the composition allows the landscape and the interior to respond to one another. Reclaimed timber and the existing timber joinery are employed throughout, while the design also provides future adaptability and the capacity to function as the principal family residence, resulting in a home where family memories and new time gently overlap.

This is a plan to reconstruct a cherished piece of land into two residences. The lot was split into two, and houses with rental portions were placed on each parcel. The composition allows the parent household and the child household to maintain an appropriate distance while still feeling a connection through their shared site. Within the constraints of a limited lot we carefully created a sense of openness and arranged living environments so that each household can enjoy a comfortable life.

A fully separated two-family residence located in a densely built residential area of the city center. Given the condition of an elongated, irregularly shaped site surrounded by buildings on three sides, a courtyard and deck terrace are placed on the southwest side—the only side with an unobstructed view. By designing it as a three-story timber-framed courtyard house, an open living environment that admits natural light and natural ventilation is achieved while screening sightlines from the surroundings. The home accommodates a dual-income couple who enjoy music and an aunt who lives with a beloved cat; it respects each household’s way of life while enabling occupants to feel close to nature within the urban context.

A rebuilding project for a two-generation residence in Nakatsugawa City, Gifu Prefecture. The site has very good views, but significant elevation differences within the site and with adjacent properties, and an aged cobble/river-stone retaining wall, made planning how to handle the grade differences a central concern.

This is a two-family house situated on a site with expansive rural scenery. To admit the fields spreading to the south and abundant daylight into the living spaces, the building is arranged elongated on an east–west axis so that each room can enjoy views and natural cross-ventilation. The parent household is located on the first floor and the child household on the second; by sharing only the entrance, an appropriate balance of separation and independence is achieved. Each floor is provided with an extended terrace to deepen the connection with the garden and the surrounding landscape. A green front yard open to the neighborhood is also included, creating a residence where the changing seasons can be appreciated and a relaxed pace of life prevails.

How should the roof be sited in this place? This residence was conceived with consideration of how it should stand as a home and relate to the street. Hipped roofs, gable roofs, shed roofs, and raised (monitor) roofs—different roof types overlap and connect, enveloping the two-family household. The roof geometry manifests as the interior ceilings, and the rich expression of the interiors bleeds into the exterior. Multifaceted ceilings and deep eaves and soffits receive, reflect, and absorb light, creating a dwelling richly articulated by the interplay of light and shadow.