多摩丘陵地帯の傾斜地に建つ築45年の戸建て住宅の改修計画。
既存建物は南東向きの傾斜地という敷地条件に対して、コンパクトで合理的な設計がされていた。 今回の改修においては、建物の外形や水回りの位置を大幅には変更せずに、既存建物がもっていた空間的魅力を最大化しながら、家族4人のための住空間と設計者自身のアトリエを併設するための整備を行う。
設計を始めるにあたり周囲を取り巻く環境を観察してみると、谷に建っているにも関わらず東西の隣地地盤が家の床を介して地続きであるように感じた。一方で、既存時点では景色を取り込む静かな空気が流れていた。そこで、家族の住まい方を考えた時に地続きの状況を家に取り込み、より動的に外界と繋がる風景を生むことで、生活空間としての可能性を広げることができるのではないかと考えた。
空間同士を仕切る境界の多くは間仕切り壁で室を区切り、それを開口と建具で繋げることで定義されている。この建物も改修前は同様の手法でプランが解かれ、各室それぞれで南面の景色や中庭テラスと1対1の関係を結んでいた。既存の室配置と形状は肯定しそのままにしつつ、空間の境界に手を加えることで繋がり方を編集し、ひいては家全体を再定義することを考えた。
既存建物がもつコの字の形式をより生かすために、リビング・ダイニング・廊下の間仕切り位置を変更し、玄関側に属していた廊下を居室側のものとすることで、視線、光、風が中庭を囲うかたちで回るようにした。次に、地上階ではアトリエの入口と中庭の出口を新設し、地下階ではアトリエへの動線を兼ねた吹き抜けを追加することで、内部を経由して外から外へ貫通するような抜けを内外開口部の配置により整理した。
ここでの境界面の編集は、壁と開口だけに焦点を当てるのではなく、建具、家具、階段、素材、構造部材など、境界面に被さるエレメントを新旧の境やサイズの大小関係なくすべて等価に扱い再構築している。内-外の抜けだけでなく、自律したモノが重なり合い、境界を越えた繋がりをもたせることで意識は自然と外へ向かい、結果として家全体が傾斜地に丸ごと飲み込まれたような空間へと変質していく。
今後住まい方やアトリエの使い方は子供たちの成長とともに変わっていく。それまで建物が歩んできた時間を止めることなく、骨格として外界に繋がりをもったこの建築が、新しく獲得した境界面を手がかりに今後変化し続けていくことを期待している。（小林佑輔）
An atelier and residence that edits the boundary surface and redefines the relationship with the outside
Renovation project for a 45-year-old detached house on a sloping site in the Tama Hills region.
The existing building was compact and reasonably well-designed for the site conditions, including the southeast-facing slope. In this renovation project, the exterior of the building and the location of the water supply system underwent minimal changes. Still, the spatial appeal of the existing building was maximized to create a living space for a family of four and the designer’s studio.
When we began designing the house, we observed the surrounding environment and noticed that the adjacent land to the east and west was connected to the ground through the floor of the house despite being built in a valley. On the other hand, at the existing point in time, there was a quiet air that took in the scenery. Therefore, we could expand the potential of the house as a living space by incorporating the ground connection into the house and creating a landscape that is more dynamically connected to the outside world when considering how the family would live.
Most of the boundaries that divide spaces are defined by partition walls that separate rooms, which are then connected by openings and fittings. Before the renovation, this building was planned similarly, with each room having a one-to-one relationship with the south-facing view and the courtyard terrace. While affirming and preserving the existing arrangement and shape of the rooms, the idea was to edit the connections by modifying the boundaries of the spaces and, by extension, redefine the house as a whole.
To maximize the U-shape of the existing building, the partitions between the living room, dining room, and hallway were repositioned. The hallway, originally located on the entrance side, was relocated to the living room side, allowing sight, light, and wind to circulate through the courtyard. Next, the entrance to the atelier and the exit from the courtyard were newly built on the ground floor. On the basement floor, a stairwell was added to serve as a flow line to the atelier, thereby organizing a passage from outside to outside via the interior through the arrangement of interior and exterior openings.
In editing the boundary surfaces, the focus is not only on walls and openings but also on fixtures, furniture, stairs, materials, structural members, and other elements that cover the boundary surfaces, which are all treated equally and reconstructed, regardless of their size and complexity. Not only is there a sense of space between inside and outside, but also the overlapping of autonomous objects and their connection beyond the boundary naturally directs the viewer’s consciousness toward the outside, resulting in the transformation of the entire house into a space as if the sloping terrain entirely engulfed it.
The way of living and the use of the atelier will change as the children grow up. We expect that the building, which has been connected to the outside world as a framework, will continue to evolve in the future, using the newly acquired boundary surface as a guide, without interrupting the time the building has spent up to that point. (Yusuke Kobayashi)
【house K/T】
所在地：神奈川県川崎市
用途：戸建住宅、アトリエ
クライアント：個人
竣工：2024年
設計：tombow architects
担当：小林佑輔
構造設計：oha
不動産：創造系不動産
施工：山内工務店
撮影：山内紀人
工事種別：リノベーション
構造：木造、RC造
規模：地上2階
敷地面積：138.7m²
建築面積：66.6m²
延床面積：108.9m²
設計期間：2023.09-2023.12
施工期間：2024.01-2024.11
【house K/T】
Location: Kawasaki-shi, Kanagawa, Japan
Principal use: Residence, Atelier
Client: Individual
Completion: 2024
Architects: tombow architects
Design team: Yusuke Kobayashi
Structural design: oha
Real Estate: Souzou‑kei Real Estate
Construction: Yamauchi Koumuten
Photographs: Norihito Yamauchi
Construction type: Renovation
Main structure: Wood, RC
Building scale: 2 stories
Site area: 138.7m²
Building area: 66.6m²
Total floor area: 108.9m²
Design term: 2023.09-2023.12
Construction term: 2024.01-2024.11
