Here Yo Shimada explains his process of designing a practical, low energy home for a family of four while respecting the surrounding topography and history:

“This is a house in the northern part of Hyogo Prefecture for a couple and their two children. The construction site is surrounded by mountains and the sky is overcast most days. I wanted to create a light, stable indoor climate and came up with a plan of three sheds of house type arranged on a 1.8 m high, grey foundation platform.

The level of the first floor was lowered to 760 mm below the ground to achieve a firm base on the natural slope, and to achieve a more stable performance of the floor heating system which is is a condensing system that utilises terrestrial heat. It was also envisaged that the whole site could be used like a garden as the rooftop came close to the ground. The site is at the corner of the entry to a residential area, and I thought that lowering the rooftop would leave wide visibility to the surroundings of the mountains and the sky, and that it would be beneficial to the whole residential area.”

Overhead courtyard

On the foundation platform I arranged three separate sheds — housing a bathroom, a sunroom and a guestroom. The bathroom shed and the sunroom shed provide lighting and ventilation for the lower floor. They form an overhead courtyard in a sense. The sunroom especially collects heat in winter, and exhausts heat in summer through its five motor-operated windows.

The three sheds do not actually provide spaces for lengthy habitation, but cover the living floor on the foundation platform. This results in privacy from neighbours at the same time as being able to watch over children playing in the garden or nearby. Accordingly, I think, both subtle proximity to and and distance from the surroundings have been realised

The residential area including the site was developed in recent years and is at the edge of fields which will eventually become building lots. It was anticipated that brand-new commercial houses would be built one after another. By designing a house as small as a peasant’s work shed of such material as vernacular as corrugated panels in an agricultural area, I anticipated a link between the prospective rows of similar new houses and the existing rural landscape.

For Free Behaviour of Things

Some box-shape volumes were required, such as storage units and a lavatory, and were made to resemble packing boxes. Through studying the method of fixing the balustrade onto the rooftop without damaging the waterproofing membrane, benches were fixed to the balustrade. A washstand is fixed to the stairwell, serving as handrail as well. The sunroom doubles as a greenhouse. Construction elements, such as handrails and top lights, are mixed together with conventional elements to serve a dual purpose. The reason for such elaboration is that I wanted to give the interiors a kind of freedom, as if everything happened to be there as bricolage. Various things the residents carry in are expected to behave freely.

Materials

Corrugated polycarbonate panels are used for outer walls of the bathroom and sunroom sheds to absorb solar radiation. Moisture and water-absorbing and heat-retaining sheets of greenhouse standard are inserted in between the corrugated panels and structure. The inside of the walls have a heat-insulating layer of clear polycarbonate hollow sheeting. The ceiling and walls of the bathroom are further insulated with light-transmitting thermal material made from recycled PET bottles.

To bring the second floor close to the first floor, 50 mm square pipes are laid around the opening that connects both levels. The pipes are sandwiched by the flooring material and the ceiling material to come up to 80 mm thickness. This opening can be closed during extremely hot days in summer and extremely cold nights in winter.

The outer walls of the foundation platform are covered with fibre-reinforced cement board. A small overhang allows rainwater to
drop easily off the edges and also provides shading. The RC part is provided with external heat insulation and broken cobblestones are laid all around it for drainage of rainwater and heat insulation.