House in Ashiya


photo by Kazunori Fujimoto

House in Ashiya

The site is located at the foot of Mt. Rokko, near the former Yamamura residence (by F.L.Wright), and it is blessed by the green scenery of the mountain.

The little heavy traffic of the road bordering the lot and the relation with the neighboring houses was the first problem to face during the design phase.

The result is a small house that strongly relates to geometrical composition and expresses well the relationship between the inside-outside space as the relationship between the family.

Two squares make a constriction in a one-room space. The first floor is divided to make different recesses in the house. On the second floor, a cross-wall divides the square. A spiral staircase is placed in the core center of the house to connect the three spaces.

Maintaining the spatial purity, we carefully considered the layout and dimensions of each architectural element to lead the ambiguous relationship between inside and outside spaces.

The opening in the living room was set at a certain height to block the view from the neighbors to ensure privacy. On the 2nd floor, the windows were placed in the center of the outer wall so that the two areas share one window.

While the surrounding wall ensures a sense of safeness to the house, the role of the windows is to open it to the outside in all directions. 

This unique spiral staircase (the center of the stair is a straight line) is designed to occupy the minimum possible area and to create space under itself that can be used as a corridor.

The curved surface of this concrete spiral staircase gives softness to rigid space.

This sculptural geometric form goes beyond the function and becomes the Yorishiro (object in which a spirit draw), which symbolizes the unity of the family.




Digitally modeled and fabricated concrete spiral staircase.

The thickness of the spiral staircase is invisible at its inner and outer end.

The beauty of the staircase lies in its invisible thickness.

Because of its helical shape, the slab does not generate a bending moment.

It is possible to resist torsion(twisting moment) and deflection only by concrete without reinforcement.

This concrete spiral staircase has a right triangle vertical-section slab combining a right and oblique helicoids in a structure.

Specifies that the top surface of the section is "right helicoid," the bottom is defined in "oblique helicoid."


flickr(House in Ashiya)