Passive Solar House with "Pit Garden"

This residence is a passive solar house based on an ancient pit dwelling. However, instead of living in the pit, the pit is used as an “pit garden” , and the rooms are located on three sides around the pit . The idea is based on the idea that the “ancestor” of the passive house, which collects heat in winter in the earthen floor, is the pit dwelling, which has a furnace in the center of the earthen floor. However, there is a crucial difference between a pit dwelling and a passive house. A pit dwelling has only an entrance and a skylight for smoke ventilation, and when the entrance is closed, the house becomes a highly centripetal shelter with the furnace at its center. The passive house, on the other hand, has a cross-section as if the south face of the pit were cut off, and the large, south-facing glass meets the outside, which greatly reduces the shelter qualities. This house solves the problem by making the pit space an inner garden. If the pit space is a garden, there is no need to act as the rooms, and the living room and bedrooms can be placed around it. However, if the “pit garden” is “useless,” there is no meaning. The south side of the “pit garden” has a large opening 5m high and 8m wide, and the north top is a tower house over 10m high that provides stable ventilation through the chimney effect. The “pit garden” plays a key role in the passive system by collecting heat in winter and storing cooling by ventilation at night in summer. Since this is just a garden, there is not any specific functions to do. No lighting is installed; the light comes on at sunrise and sets in the darkness after dusk. The residents entrust the blessings of the sun and the wind to this “pit garden”.

We wanted the “pit garden” to be like the outside of the house, so the “pit garden” was to be surrounded by a galvanized steel shingle roof. The floor of the “pit garden” is the base of the reinforced concrete foundation itself. It is a rough floor with no decoration.On the other hand, the rooms surrounding the “pit garden” are calm spaces wrapped in wooden boards. Therefore, the contrast between the inside and outside of the “pit garden” is very strong. For the surrounding rooms, the “pit garden” is like an external space, and when one enters the “pit garden,” one feels as if the sky and the earth are connected.

The site is located in Iwata City, Shizuoka Prefecture, Japan, in a typical detached residential area. The house is not concerned about the neighbors, as the “pit garden” provides a buffer from the outside. While neighboring houses have thickly planted gardens to block the eyes of neighbors, this house's exterior garden is unplanted and paved with crushed stone. The outside garden becomes a light garden for the neighborhood, and conversely, this garden allows people to enjoy the neighborhood's plantings from the outside garden.

Dimensions
Site area: 327.13m2
Building area: 102.94m2
Total floor area: 136.63m2
(1st floor area 77.01m2, 2nd floor area 59.62m2)
Structure
Conventional wood structure -Tenryusugi: Japanese cedar cut in north mountain area in Shizuoka pref.

Client: Syunya Takahashi
Design (architect): Kikuma Watanabe
Design (company): D Environmental Design System Laboratory
Structure Design:
Syunya Takahashi D Environmental Design System Laboratory
Construction:
Kuwataka Kensetsu Co.,ltd