SHIRASU
~ Sustainable-House with Volcanic soil brickwork.
The resident did not rely on energy in South Kyushu of high temperature and humidity, and hoped for ecology life with the environment.
The wind of land is felt, rain water is saved, and it enjoys gardening. It is native life. The site is a residential quarter that extends on a Shirasu plateau near from the Kagoshima City downtown. I then thought native house(Sustainable-house) with the soil (Shirasu) as the material that formed this plateau native by the made Shirasu block.
Shirasu has a lot of characteristics in other geological features like fireproof, adiabaticity, the humidity conditioning, thermal storage, and lightness, etc. without. Pressurizing and construction it the technology of a monotonous block in Shirasu for the pavement that had begun to spread in the city was made the best use of, and production with the block for the construction of Shirasu was tried for the first time. To secure material strength, the outside wall block changed mixing Shirasu. It inlaid with the raw ore of Shirasu to improve the adsorption and desorption of moisture to the inner wall block. At the same time, The character of this Shirasu appears as an expression of the memory accumulating to the block. The house where in all outer had been piled up on an inside and outside midair layer double wall became a space wrapped in the soil like the cave in Shirasu.
This inside and outside midair layer double wall has reduced the thermal loading to the inside. In addition, the inner wall block surrounds like finish in any room of the house, and adjusts the indoor humidity. Therefore, the inside is chilly cool, and warm summer in winter. It is a steady throughout the year thermal environment. It proposed the energy performance of underground resources accumulated in the Shirasu plateau.
And House of Shirasu block masonry which reused the volcanic soil, is the new Sustainable-house of environmental recycling.
Sustainable feature:
As previously described, The most effective sustainable feature of this house is the double wall of Shirasu block.
In addition, playing an important role is the green roof that put grass on top of the Shirasu block.The green roof of the Shirasu block, lightweight Shirasu block plays the role of soil. Therefore, it is to reduce the burden of the roof load.The green roof of the Shirasu block, also can improve housing energy efficiency while positively impacting the quality of the urban environment.
Others: Solar water heater panel, Water storage system of rainwater reuse.
Spatial strategy:
The shape of the plan is matched to site shape facing the corner lot. The cross section, so as not to give intimidating to the surrounding environment, so as to enclose the interior, is tilted. As a result, it became appearance like the plateau united with the sloping ground.
For better ventilation, plan layout was one room space through the atrium to the second floor with no partitions. By the chimney effect, trapezoidal cross-section type, enhance the efficiency of ventilation from the top light on the second floor warm air on the first floor.
Sustainable materials:
・Outer wall block is using Shirasu block.This block has been molded by mixing the cement and particles of Shirasu.
・Inner wall block is using the Shirasu block with inlaid gemstones of Shirasu.
Shirasu is a soil of volcanic ash that could be due to deposition of pyroclastic flows and jet source of Kagoshima Bay & Sakurajima 25,000 years ago. (Please see the picture of Sakurajima attached.)
・Shirasu block manufacturer : Stoneworks (http://www.stoneworks.co.jp/)
Stoneworks is a manufacturer of paving blocks as raw materials Shirasu. This technology is patented.
Site context/challenges:
The site, for the southwest corner lot that is gently sloping, there is no house to block the sunlight. Therefore, the house receive all day, the strong sunlight.
On the other hand, since the land and sea breeze (local wind) that Shirasu plateau gives birth is dominant to the northwest, the wind circulation is good.
Shirasu block produces the effect of this sunlight suppression, creating a wall of ventilation.
One more special climatic conditions, is the ash eruptions of Sakurajima in Kagoshima. Shirasu block is made from a Shirasu that this ash was deposited. Therefore, Shirasu block is a sustainable material that not dirty ash fall, and continue to aging.