Hair Room Toaru Beauty Salon | Saitama, Japan | 2023

Architects: Ateliers Takahito Sekiguchi
Lead Architect: Takahito Sekiguchi
Associate Architects: Shinmei Kosan
Landscape Architects: Onshitsu, Yuichi Tsukada
General Contractor: Yagi Construction
Client: Hair Room Toaru
Photographers: Yosuke Ohtake

This is a beauty salon located on a local roadside. Cars come and go all day long on the front road and most of the surrounding area is occupied by parking. But three-fourths of the city area is covered in forest, where forestry is flourishing here and timber has long been transported by raft. Although the utilization of local resources is being promoted, the transition to wooden non-residential low-rise buildings has not progressed.

The client requested bright spaces, ventilation performance effective against viruses, and a sustainable architecture to ensure this. Is it possible to create a natural architecture that reflects these diverse conditions? Rather than thinking about the design or form, the architects started thinking about architecturally recombining the hair salon, the townscape, and objects. Cut spaces with large mirrors (RC walls) that exceed human scale are arranged in a staggered manner, and large wooden desks (CLT roofs) are placed between them. They are joined using the same simple construction method as furniture using only angles and screws. RC walls can handle out-of-plane loads, and CLT roofs create long-span frames without beams.

They use right materials in right places for fire protection and environmental performance, and maximize the expression of wood grain while reducing weight, heat load, and cost. Indirect light shines in from between the roofs, and the wind flowing along the roofs promotes effective gravity ventilation without raising hairs. Plantings are amplified by reflection, creating an environment surrounded by greenery. By replacing the timber that was once washed away with roofs and incorporating the reflections of cars on the roadside, the flowing landscape of the past and present is superimposed on the building.

The small activity elements of the hair salon transcend meaning, purpose, and scale, creating a natural architecture in which objects are mixed in a multilayered manner. By using RC for the walls that require fire protection and using CLT made from local wood for the roofs, it is possible to maximize the wood grain.
As a result, it is possible to reduce the building weight by 1/3, minimize foundation work and ground improvement, and reduce heat load by 1/3 compared to RC buildings. By constructing the CLT roof with a size that allows it to be transported flat on a single 10 ton truck, and by using CLT for curtains and furniture, the architects have achieved a motherboard yield rate of 94%. With the rolling tower, temporary construction work can be minimized and roof work can be completed in five days, shortening the overall construction period by one month.

The exposed CLT roof prevents direct sunlight, the openings between the roofs provide sufficient natural ventilation and seasonal breezes, and the Low-E double-glazed openings and high-performance LED lighting reduce electricity usage. It can minimize carbon dioxide emissions from both the operational and construction aspects, and can be achieved at the same cost as reinforced RC buildings. It is possible to create sustainable architecture while making use of the city's abundant forest resources.