This is a convention hall located in Naka-ku, Nagoya City. It is built on an approximately 1,500 square-meter site, on top of the station where two main subway lines cross, and facing two roads: main road on the north side and a neighborhood road on the south. It was required to show “two faces” for this building. The facade on the north side facing the main road is its face as convention hall with a capacity to accommodate over 600seats. On the south side is its face as a commercial building with a café on the ground floor and spaces above for future tenants. So the building was designed with a distinctive difference in the two faces facing north and south.
Since this building has very few openings on the north facade, it was very challenging to design the walls. First, PC panels of polished white concrete was used as the exterior wall material. Then these panels were reinforced with vertical ribs to add a sense of scale and rhythm. At the same time, these ribs serve as a vehicle to show the movement of light and shadow following the sunlight.
For visitors entering from the north side, the most important encounter with this building will be the lead way to the entrance on the second floor and the approach from the second floor, up to the top floor by elevator, to the prayer hall. This is why, the lead way from entrance to the atrium on the second floor was to be extended as much as possible. This was not just to physically create a long distance, but also to make a passage to spiritually transform oneself.
First, visitors will enter inside by meandering through the two floating, semi-transparent glass screens. The entrance hall is designed as a space with controlled natural light coming in, thus slightly dim. There and then, the grand staircase appears, connecting to the main area on the second floor. As the visitors climb up the stairs, they are met by all the natural light shining through the skylight, placed at the top of atrium, high on the second floor.
The atrium has the ceiling height reaching over 25 meters and exposed solely to the sky above through the skylight. It presents such a contrast to the relatively low ceiling of the entrance hall on the ground floor, and the lights in this such a bright, light filled space change constantly like a sun dial following the movement of the sun.
The concept for the prayer hall on the top floor was to be a white, abstract space, as well as a space close to nature created with natural lighting. This is one of the reasons why the prayer hall is located on the top floor and the roof is constructed with a light form of sheet steel ribs. Actually these ribs, of 19mm-thin sheet steel running parallel on the ceiling, support the roof and are not just ornamental device. Furthermore, skylights were placed on both right and left top walls. The intention of this design is to create white, abstract walls and simultaneously, the recycled glass material and the natural backlight from the skylight, enhance the texture of the walls. All these effects derive from the design concept of producing an abstract space, filled with, not artificial but natural lights, creating bright white walls and projecting changing images with the course of time.