WOHNUNG+GESUNDEIT (「住まいと健康」/ドイツ）2018 Winter Nr.169 English Text
Shell House / Language of forest
Shell House/ MO RI NO KO TO BA (Language of forest)
I t is a small villa in the forest of Nagano prefecture in the middle of Japan.
The seven beams born from the dynamic and organic earth wall are expressed the cycle of life of the human and universe. And the two inscribed circles represent the correspondence of them being opened while closing. It is an architecture born from the earth of the area and speaking to the human, returning to the earth.
The requirement from the client is the villa as "unusual and beautiful that does not feel oldness even after a long time architecture" and there was the strict landscape regulations of the resort area that the building coverage and floor area ratio was 20% on a narrow site area(290m2.)
Following that an organic form into the surrounding forest was born which is opening to the east / south side that waterway flows for captures sunlight and heat and closing the north / west side of the street and neighborhood.
And we aimed to construct this house by satisfying contemporary energy-saving standards be a norm with less environmental impact, with local FSC wood and earth and people's hands without relying on petrochemical materials.
It is a dome having a roof and a wall integrated with a wooden shell roof structure that combines a
two circle .
All the interior rooms are made of local earth and solid wood. The earth wall of the curved form is gently enveloped the whole space. When drawing in a wooden sliding door that have large glass which is also a feature of Japanese architecture, the interior becomes integrated with the forest through the wood deck.
On the 1st floor, small stepped floor changes the quality of the space that is sitting as a bench normally with sanitary and toilet in the back of continuous wooden doors. 2nd floor that was made from local pine wood change to the bedroom by using futon.
■3 Social proposal
It is made by traditional construction method using traditional material of trees and earth returning to the earth without using laminated wood and plywood with harmful potential to the human body.
This structure is that having wood pillars and bundled curved seven beams with a central circular wood and a structural wooden shell roof over it. The form seems to be special, but it is made according to Japanese traditional wood structural method. It shows the main log pillars, beams and bundle as a representation in the ceiling and walls of earth so that the skilled carpenter. More than 2.7 m over-hanged roof are constructed by the "Hanegi" which is also traditional Japanese wood structure by lever principle.
Not only inner rooms are made of earth and wood, but also background wall is also used sliced solid wood without using gypsum board etc. of the petrochemical construction material.
A fireplace were made with rammed earth using local earth by handmade.
■5 Advantages: Beauty and comfort
By the effect as above, the appearance is organized to fit the surrounding forests, and the interior is made up of a comfortable space by curves.
■6 Reduction of environmental impact
It is important to use materials with small environmental impact and low production energy. The following is the initiative of this house.
Prefecture-produced · prefecture domestic material 100% use of trees and earth.
· Structural timber is certified by FSC and COC. Forest certified material
· Furniture and doors are made of regional materials and craftsmen in the area.
These will shorten the transport distance of materials, reduce the environmental burden, protect local trees, people and technology, lead to the next generation.
■7 Energy saving performance
Outside wall, roof and ceiling average heat transmission coefficient UA = 0.49. (W/m2K), Japanese environmental assessment CASBEE S rank ☆ ☆ ☆ ☆ ☆ and satisfying the design primary energy consumption standards in Japan reduction of 11%.
The large opening in the south is designed passive design it stores winter solar heat accumulating inner wall of the earth, and has an effect on the thermal stability of the room.
The coating thickness of the soil wall is 35〜40 mm, not as so thick as but combined with 180 mm wool insulation material, the wall has high insulation performance as U = 0.203 (W/m 2 K). Curved wall added accents to the space such as indirect light and niche for display.
In the 21st century, there is a need for an architecture with regional identity that is integrated with the earth, which does not impose a burden on the global environment.
I hope this house will be one of the responses from Japan.