Project in Detail
Koji Tsutsui & Associates, Tokyo, Japan
World Architecture Festival 2011 - Category Winner
South Elevation: Cottages & Thin Folding Roof
The client chose a sloped site surrounded by Japanese larch trees in a mountainous region of Karuizawa, Japan, (an hour commute away from Tokyo on a bullet train) as the ideal location for their home. This 178sqm house sits on an artificially leveled area of the site created thirty years ago and left unused. Since the client wanted a house that seamlessly blends into the natural surrounding, topography and local culture, we designed this house as a cluster of small mountain cottages.
It consists of five single pitched roof cottages that are clad in the local larch wood siding. Rather than using a complex construction technology, it is built in a traditional Japanese wood construction method so that local builders can skillfully craft each structural wood member. Each cottage varies in size to fit its function and set on site at 30 degree increments to best fit the topography and to face unique views. All cottage roofs have varying slopes and overhangs that touch the adjacent overhangs, creating gap spaces between these cottages, a simulacrum of alleys in a city. The triangular "connecting" roofs span between these overhangs to capture these gap spaces as a single fluid public interior space, which serves as a living room or circulation and feels like being outside looking at mountains in the distance. Since these connecting roofs bend & fold to connect the cottages at multiple angles & heights, the in-between space result in a spatial & structural warpage.
The design intent of this house is not the final architectural form, but rather, establishing a set of design rules of cottage placements and connections, which allows the house to be freely arranged to satisfy any requirements and adoptable to any future changes or additions, prolonging its building life.
For sustainability, this house uses a modern technology for heating and a traditional method for cooling. During winter time in Karuizawa, the temperature drops to -15ºC, and to heat the house, electric radiant heat panels are installed right beneath the concrete floor slab, which generates heat during nighttime and shuts off during daytime while the clients are away for their work. This heating system is highly efficient since it uses soil beneath the foundation to retain heat and takes advantage of Japan's lower electricity cost at off-peak hours. During summer time, natural ventilation, enabled by operable windows located at each end of the in-between space and in each cottage, allows continuous air movement to cool the interior space.
Koji Tsutsui & Associates
Koji Tsutsui & Associates
Mr Hirotsugu Tsuboi
Hirotsugu Tsuboi Structural Engineers