【多重な採光・環境レイヤー装置群〜 i-works参観4】

　さて i-works参観4。きのうも触れた家のメインの窓回りです。現在は三角屋根の落雪方向からの雪に閉ざされているけれど、この窓外にはウッドテラスと造作された庭がある。積雪のためそこまで取材できなかったけれど、かなり力点の置かれた庭園造作と推認された。それと木製３重ガラス入りサッシ（NORD社製とのこと）が結界を構成している。
　その中間には横桟の外部建具、一種の雨戸とも思える装置が備えられていた。外部とは一定の空隙があり、折からの「暖冬」傾向もあって建具動作には支障はないようだった。また、屋根からの水分落下ラインとの間には軒天の距離が取られていた。
　その窓面から、内側には最外側に「網戸」が建具収納されている。木製窓にちょっとゴッツい手動用取っ手があるので、その分、後退距離が取られていた。
　そして、現場では最内側に障子が収納されていて、それが開閉されることを確認した。ただ、その網戸と障子の間にもけっこうな距離があって、なにか建具が収納されていたようだったけれど、確認できていなかった。
　床面を見ると、パッシブ換気と床下暖房からの暖気上昇用の開口部が仕込まれていた。この木製サッシとの距離感が内部用の建具収納スペース分、けっこう目視的には30cm程度ある。このような建具仕様がどのように環境性能的な結果に結びつくのか、あまり目にしたことがなかった挑戦かも知れない。
　建具の重層による効用としては、外部の採光に対してそれを複数のレイヤーで室内に導入させるというメリットがある。数寄屋建築が象徴する空間性とは、そういった採光レイヤーによって「やわらげられた」光環境を室内にもたらすことなのだろう。縁側や軒の出なども含めてそれが日本人的な感受性、コトバで言えば「空気を読む」みたいな人間相互の「思いやり」のような心象を育成・涵養してきたとも思える。
　考えて見るとわたしたち北海道の住宅では、そういった心象への「配慮」はひたすら空気環境の均一性・快適性のいわば「物理的」な方向一択だったかも知れない。このような挑戦が、どのように北海道民に受け入れられていくのか、興味深いと思った次第。わたし自身は1991年、いまから34年前にブロック構造の外断熱という、従前の日本建築とははるかに距離感のある選択をしたけれど、現代ではむしろこうしたチャレンジがあるのだと認識した。


English version⬇

Multiple lighting and environmental layering devices - i-works visit 4
　I myself chose a non-traditional residential architecture of non-timber-framed concrete blocks with external insulation, but times are changing. ...

　Now i-works visit 4. the main window area of the house, which I mentioned yesterday. It is currently closed off by snow falling from the direction of the triangular roof, but there is a wooden terrace and a garden outside this window. We were not able to cover that much of the garden due to the snowfall, but it was considered to be a very important part of the garden construction. The wooden triple-glazed sash (made by NORD) forms the boundary between the terrace and the garden.
　In between, there was an external fittings with horizontal piers, a kind of storm door. There was a certain amount of airspace between them and the outside and, due to the occasional ‘mild winter’ trend, there seemed to be no problem with the operation of the fittings. There was also a distance between the eaves and the moisture fall line from the roof.
　From that window face, the outermost ‘screen door’ was fitted and stored on the inside. The wooden window has a rather lumpy manual handle, so a setback distance was taken from that.
　And on site, a sliding door was stored in the innermost side, which was confirmed to be opened and closed. However, there was also a considerable distance between the screen and the sliding door, and it seemed that some kind of fittings were stored there, but we were unable to confirm this.
　Looking at the floor, there was an opening for passive ventilation and warmth rising from the underfloor heating. The distance between this wooden sash and the internal fittings storage space is approximately 30 cm visually. It may have been a challenge to see how such a fittings specification could lead to environmental performance results, which we had not seen much of.
　The benefit of the multiple layers of fittings is that they allow multiple layers of light from the outside to be introduced into the room. The spatiality symbolised by sukiya architecture is probably to bring a ‘softened’ light environment into the room through such layers of lighting. It seems to me that this, including the veranda and eaves, has nurtured and cultivated a Japanese sensitivity, or in other words, a mental image of mutual consideration for each other, like ‘kuki wo yomitaku’ (reading the air).
　When you think about it, in our houses in Hokkaido, the only ‘consideration’ for such mental images may have been in the ‘physical’ direction of uniformity and comfort in the air environment. It will be interesting to see how this kind of challenge will be accepted by the people of Hokkaido. In 1991, 34 years ago, I myself chose to build a block structure with external insulation, a choice that was far removed from the traditional Japanese architecture, but I am now aware that such challenges exist in the present day.