Grand Room House
GRAND ROOM HOUSE
Igarchitects
ARCHITECTS
Igarchitects
LEAD ARCHITECT
Masato Igarashi
CONSTRUCTION
Kentaro Okata GALAS Inc.
ENGINEERING
Structure: Yousuke Misaki EQSD
DESIGN TEAM
Igarchitects
PHOTOGRAPHS
Ooki Jingu
AREA
145 m²
YEAR
2025
LOCATION
Saitama, Japan
CATEGORY
Houses
English description provided by the architects.
The site is located on the edge of a residential development surrounded by a rural landscape, facing both a busy road and a private lane.
The client—a family of four consisting of a couple and their two young children—desired a generous, flexible home that could accommodate changes in their lifestyle as their children grow.
The design takes advantage of the spaciousness and openness offered by the large site and its surrounding environment to create a bright and expansive space.
The building consists of a single large space called the Grand Room, around which private rooms are arranged.
Occupying half of the building's total area, the Grand Room functions as a living room, dining room, hallway, play area for the children, and even as a garden.
Its usage can change flexibly, guided by the overhead beams running through the space.
Positioned between the "town" and the cluster of private rooms, the Grand Room serves as a transitional space that connects two environments of differing scales.
It becomes a generous void that receives and mediates the activities and objects from both the private spaces and the outside world.
To realize this 5-meter-tall open volume, it was necessary to secure surface rigidity and ensure out-of-plane resistance to wind forces.
While typical solutions might involve catwalks, dropped beams, or diagonal bracing, this house employs a zigzag beam system that performs the functions of both beams and braces.
Using only a single type of linear structural element, this approach achieves a unified yet dynamic spatial structure.
The zigzag beams add depth vertically and perspective horizontally, enhancing the sense of openness.
They also double as lighting rails and help define zones within the space.
Rather than defining rooms by their conventional functions—like "living" or "dining"—this house centers around a non-prescriptive space capable of accommodating multiple activities.
This generous, adaptable void ultimately defines the character of the home and reflects the way of life the clients envisioned for their time here.
