House in Byobugaura is a family home for a couple and their two children, situated in Yokohama Kanagawa, Japan designed by Takeshi Hosaka Architects. Located on a narrow plot of land of only 60 square meters, the architects could only build a footprint of just 30 square meters. To add additional space to the home, they built a basement floor and added two levels above ground floor per 30 square meters. The floors were designed to curve near all of the windows, allowing natural light and air to penetrate throughout all of the floors, particularly at basement level. This move increases the total floor area by a third.

In this open plan architecture, beautifully made furniture sits in the space as objects in a landscape. The pieces within this “roomscape” divide the space without the need for walls, but they also add warmth, as they are detailed in polished timber along with the floor finishes. Together they provide a textural contrast with the insitu concrete walls and soffit.

A steel spiral stair brings a more flamboyant sculptural sparkle to an admirably restrained space and where the circular hole for the stair cuts through the curved floor, a deformed circle is created that gives a tactile edge to the concrete. It just makes you want to touch it.

The exterior front and rear exterior elevations are simple. Three equal bands of glazing suggest a three-story building. It is only the heavily curved soffit that gives any indication that much of the space is actually below ground.

Photos: Koji Fujii Nacasa&Partners Inc