a+u Architecture and Urbanism Magazine

Shingo Masuda Katsuhisa Otsubo Initiative Roof

A residence for a married couple in a suburban residential neighborhood outside of Tokyo. The new design inserted insulation into the existing 45-year-old steel-frame main house and wooden-frame annex, and connected the two with a roofed corridor. The thin roof is made of 4.5mm-thick steel plates and 70-mm steel square poles, and measures 5.65 meters high by 17 meters long. It was intended to create a strong presence that would not be overshadowed by its surroundings, while appropriately connecting the place and its inhabitants, as a sort of iwakura, the site that enshrined a deity in the animistic Shinto religion of ancient Japan, taking the form of a boulder or large stone.

The roof surface is slightly parabolic, differing 9 cm from one extreme to the other. Rain chains pull down on the roof and draw rain water to flow down like a downpipe.

The square poles are placed at 4.8-meter intervals, and they are connected to upstanding H-beams with rigid joints to form a Rahmen frame. The steel plates bring in reflections of the surrounding greenery.

The main house was constructed 45 years ago but it had no structural defects nor any functional problems in aspects such as ventilation, so the renovation mainly focused on insulation, maintaining a continuity with the existing landscape of the property.