ITOI Group Holdings, rooms and offices all in wood

The office and other rooms are located on the south side, and restrooms and locker rooms are located on the north side on the first floor. The second floor is accessed via a spiral staircase in front of the entrance, and serves as a rest area for staff members. The terrace overlooking the Teshio-dake Mountains are located on the west side, serving as an amenity space open to the community.
The walls, second floor, and roof are made of CLT panels, and the CLT slab is double-layered to maintain and allow the office space to be column-free. The maximum size of the CLT panel is 7735 x 2200, which is the maximum size to be loaded on a standard trailer. The CLT panels of the exterior walls is a V-shaped structure, and the structural analysis was
The project is a new building for a company that has been engaged in lumber processing, civil engineering, driftwood disposal, and welfare work in Asahi-cho, Shibetsu-shi. The site is located at the entry of the road from the center of Shibetsu City to Asahi-cho, and is surrounded by rich natural landscape with a view of the Teshio-dake Mountains to the west. The floor plan is long in east-west direction to provide good lighting and a view of the mountains from the main room, with the aim of creating a form with a strong presence appropriate for a leading company in the region.
The office and other rooms are located on the south side, and restrooms and locker rooms are located on the north side on the first floor. The second floor is accessed via a spiral staircase in front of the entrance, and serves as a rest area for staff members. The terrace overlooking the Teshio-dake Mountains are located on the west side, serving as an amenity space open to the community.
The walls, second floor, and roof are made of CLT panels, and the CLT slab is double-layered to maintain and allow the office space to be column-free. The maximum size of the CLT panel is 7735 x 2200, which is the maximum size to be loaded on a standard trailer. The CLT panels of the exterior walls is a V-shaped structure, and the structural analysis was performed using the Route 2 method, which achieves higher wall rigidity than a rectangular structure close to the arch shape.
Pull bolts and long screws were used for the CLT joints, aiming to create a simple and natural expression without exposing any hardware on the surface. C The office is a column-free that can flexibly accommodate meetings and various events by moving furniture. The V-shaped LT panels create a visual change and a sense of expansion into the sky to the horizontally expanding landscape, and add a visual layer that expresses the vitality of an open and evolving company to the space.
For heating, driftwood and wood from the Teshio River were collected and turned into chips to be used a hot water floor heating system powered by a biomass boiler, saving energy and reducing CO2 emissions by 12.5㎥per year for the spaces, and 1.23㎥ per year for lighting, a total of 13.73㎥ per year. The project aims to contribute to the community by addressing the SDGs in a holistic manner, including business development aligned with the local community.
Floor Plan
Taking into account that the company's main business is civil engineering, our design focuses on creating an office space where many employees can gather and interact with each other at the end of the day.
Since the office space is also used as a place for in-house training and presentations, a high ceiling and a column-free space were created by using CLT panels for the ceiling.
Since the number of employees in attendance varies depending on the season and time of day, our idea was to place a foyer, meeting rooms, and other rooms around the office space so that employees can change their work location to suit their needs and the number of people present. The entrance for visitors is located along the main road on the north side, and rooms including the library, foyer, kitchenette, and restrooms are located on the north side. The ceiling is lowered to consolidate ventilation, air conditioning, and electrical piping in the ceiling plenum. The president's office and the office space, which had been located on separate floors in the old building, were placed side by side on the office floor in this building to create an environment that facilitates a more open communication.
The second floor is accessed via a spiral staircase in front of the entrance, and serves as a rest area for staff members. The terrace overlooking the Teshio-dake Mountains are located on the west side, serving as an amenity space open to the community.
CLT Construction Method Using Hokkaido-grown Wood
Todo fur grown in Oketo-cho, Hokkaido was used as the material for the CLT panels, which were used to construct the exterior walls, second floor, and roof. Since Shibetsu City is located in the special heavy snowfall area, we modeled the walls with an effective cross section consisting of inscribed rectangles of parallelograms and trapezoids to create an arch effect as a rational wall configuration for snow loads, and treated the beams on the tapered portions as rigid zones.　The characteristic wall configuration, in which the CLT wall panels and the shape of the openings are the two sides of the same coin, is exposed both inside and outside the building, creating an elevational design that symbolizes the company's role as a leader in this region.
In terms of the structural plan for the office space, the second floor consists of two types of panels made of 5-layer and 7-ply (t=210) and 5-layer and 5-ply (r=150) Todo fur wood, which are glued together and joined from the top and bottom with Paneleads, to construct a column-free space with a width of 7.7m using only CLT panels. As a result, the space is flexible enough to accommodate an increase in the number of employees or changes of desk layouts due to changes in departments.