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Architects: New Material Research Laboratory
- Area: 313 m²
- Year: 2022
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Photographs:Masatomo Moriyama
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Lead Architects: Tomoyuki Sakakida, Aki Tsumura
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Structure Engineers: Masaki Structure Laboratory Limited, Masaki Structural Laboratory
Text description provided by the architects. We designed this courtyard house on a roughly 330m² (100 tsubo) plot halfway up a hill in a quiet residential district. Since the site features a height gain of 2 meters, we adopted a split-level floor format across a north building and a south building to fit with the topography. The plan was to create a courtyard house that it was impossible to see directly from outside, and we opted for a very private layout in which every room offers a view of the serene garden. Because there is enough natural light coming in from the garden, we made the south-facing façade into a “closed” design with no windows of any kind. We wanted to make an exterior that conjures tranquility and reticence, at the same time as the vertical tongue and groove solid-wood siding with equally spaced battens provides a visual accent.
The structure of the building is of mixed construction: the first floor is of reinforced concrete while the second uses wooden post and beam construction. The reinforced concrete construction part surges up like a platform, shouldering the ground alongside it, while the upper part is composed of a hand-crafted post and beam framework. The ridge beam—a 10-meter length of Tohoku pine from northeast Japan with an adze-applied naguri ¹ finish—is the key element in the space. Shinshu larch is used for the wooden sash windows that give on to the courtyard garden, and the character of the wood, which has a certain redness, harmonizes with the specially made stoneware tiles and the scratched finish of the plaster. For exterior elements around the house, we used antique paving stones from a tram bed for the entry path and Aiki stone for the stone walls bordering the garden. For greenery, we planted evergreen Japanese yew and pines; in the courtyard garden, meanwhile, we planted deciduous trees that change color in the fall, giving a sense of the changing seasons throughout the property. The living-dining area was designed so that its floor, which is at the same level as the courtyard garden, feels like a continuation of it.
Exploiting the peculiar character of the split-level design, we kept the roof of the south building low so that it looks like a single story when viewed from elsewhere inside the house. The hip-and-gable roof with drooping verges at the ends is covered with straight-edged copper tiles and topped with a ridge of two-tiered noshigawara tiles.² When it comes to the wooden elements of the roof, we left the rafters and sheathing exposed, and kept the height of the partition walls down to show that the individual spaces are part of a larger whole and to make the wooden framework visible throughout. For the wooden body of the house, we used conifers, chiefly Tohoku pine and Yoshino cedar. For the joinery, we went for Yanimatsu pine, Yakusugi cedar, and chestnut, while also indulging our fondness for South Sea woods such as Indian rosewood, Myanmar teak, and mahogany. For stone materials, we used Oya and Tatsuyama tuff, hard sandstone from Isahaya, and Katsuren travertine from Okinawa. Overall, we did our best to create a space where Japanese materials always play the central role.
The staircase that links the south and north buildings has a window. We gave the staircase a gentle incline and rather deep treads to create a line of movement that suggests two spaces seamlessly conjoined. The crucial thing about the house is the care with which any changes in the sightline vis-à-vis the courtyard garden are managed. As a result, the floor level can change without your even being aware of it.
We did not want to have to build the normal fire-resistant structure required in Japanese cities under the building standards law, so we spread the building out on the generous 330m² sites, meaning that it could be a fire-preventive structure instead. Our scrupulous attention to the legal niceties earned us comparative freedom in the handling of the wooden parts of the exterior walls and the eaves, and the interior ceilings, something that made a positive contribution to the overall design. When seeking to increase the amount of wood-based construction or post and beam construction in urban areas, Japanese architects are under an obligation to meet the authorities’ fire resistance standards. But because of the many rules governing where natural wood can and cannot be used, construction using more wood and post and beam construction (both relatively easy to carry off in country villages) is simply unworkable in cities.
There is, however, something terribly sad about city streets made up of nothing but buildings with the proper level of fire resistance. We hope to clearly set forth the various challenges that wood construction faces in urban areas and then seek solutions for them. Carpenters with the necessary skillset are an essential part of any solution. The recent quest for simplification and efficiency, and the resulting use of pre-cut lumber and ready-made joints, has prompted a uniform decline in the level of craftsmanship. Practicing architects thus have a threefold duty: We must tell the world about the wonders of skilled carpentry, help foster the individual creativity of carpenters with the skills to cut and shape wood for themselves, and we must give them the opportunity to put those skills to work.
