5/20 発寒の家Ⅲ

 5/20（土）の「発寒の家Ⅲ」。本日は外装の解体が終わったので・・構造体の傷みを確認しに行ってきました。その結果は・・まあ予想通りといいますか、今の工法は進化しているなあと感じた次第。さてなぜ外装を解体して構造材の傷みを確認することが大切なのかと言えば、こうした通気層（排水機能）も防湿層も持たない時代の建物は柱、梁の外気側に深刻な被害が集中し易いからです。平たく言えば壁の中で温度が最も下がり易い外装の裏側（柱の外気側）は結露に対しても、雨水等の漏水に対しても一番の弱点。注意点は・・室内からではまず分からない事。今日も一緒に点検にお付き合いください。

写真から得られる教訓は、たとえ軽微な部分断熱改修であっても、土台の下から上に45ｃｍ程度、中間胴差から上下に45ｃｍ程度はぐるりと開口して構造の傷みを点検し修理すべきということです。在来木造の傷みはこの部分に集中しやすいですから。

“Hatsu no Ie III” on Saturday, May 20th. Today I finished dismantling the exterior, so I went to check for damage to the structure. The results were...well, as expected, but I felt that the current construction methods were evolving. Now, the reason why it is important to dismantle the exterior and check for damage to the structural materials is that buildings from the era that did not have ventilation layers (drainage function) or moisture-proof layers suffered serious damage to the outside air side of columns and beams. Because it's easier to concentrate. To put it simply, the back side of the exterior (the outside air side of the pillar), where the temperature is most likely to drop among the walls, is the weakest point against condensation and leakage of rainwater. One thing to keep in mind is that you can't really tell from inside the room. Please join us for an inspection today.

The lesson learned from the photos is that even if the partial insulation renovation is minor, it is necessary to open the base approximately 45cm above the base and 45cm above and below the intermediate shell to inspect and repair damage to the structure. about it. Damage to traditional wooden structures tends to be concentrated in this area.

北側の柱（と）の（１）番。室内側からは何ら問題なく見えますが・・・

Number (1) of the pillar on the north side. It looks fine from the inside, but...

外から見ると要交換です。

From the outside, it looks like it needs to be replaced.

窓の左側の柱が1/3くらい腐ってなくなっています。モルタルの裏が結露したか、サッシの際からの漏水か、はたまたその両方か？シージングボードと柱の間に水が溜まり柱を外側から腐らせています。

About 1/3 of the pillar on the left side of the window is rotten and gone. Is there condensation behind the mortar, water leaking from the edge of the sash, or both? Water collects between the sheathing board and the pillar, causing the pillar to rot from the outside.

こちらは同じ場所を室内から見たところ。シージングボードこそ傷んでいますが柱は無傷のように見えます。

This is the same place seen from inside. Although the sheathing board is damaged, the pillars appear to be intact.

5/19 発寒の家Ⅲ

足場が掛かった「発寒の家Ⅲ」、工程としては二階の天井まで解体が完了し二階の小屋裏まで全て目視点検が可能となりました。印象に残ったのが・・１階と２階でモルタルの下地が異なること。最初の確認申請が出された1981年、モルタルの下地は12ｍｍのバラ板の横貼。それから８年後の1989年に２階を増築した際に使われたのはなんと耐力面材のシージングボード。当時はまだ筋交いの代わりになるという意識は薄く筋交いと併用されています。このシージングボードが中々曲者で・・ラスを留め付ける又釘が室内側に飛び出しその先端が壁内結露して円形の染みを作っていました。外付けアルミサッシの端部も漏水か結露水でシージングボードはブヨブヨでした。多少濡れても腐敗限度内なら染みだけで持つ木材と少しでも水が入ると破綻する新建材・・製品差以上に壁内に水分が入らない断熱構造とデイテールは設計者の大切な仕事だとあらためて感じました。

The construction process for ``Hatsuno House III'', which had scaffolding on it, has been completely dismantled up to the ceiling on the second floor, making it possible to visually inspect everything up to the attic on the second floor. What impressed me was that the mortar base was different between the first and second floors. In 1981, when the first application for confirmation was submitted, the mortar base was horizontally pasted with 12mm loose boards. Eight years later, in 1989, when the second floor was added, sheathing boards, a load-bearing material, were used. At that time, there was still little awareness that it could replace braces, and it was used in conjunction with braces. This sheathing board was quite crooked...the nails that hold the lath in place stuck out on the indoor side, and the tips of the nails were condensing inside the wall, creating circular stains. The edges of the external aluminum sash also had water leakage or condensation, and the sheathing board was shaky. Wood that can withstand stains even if it gets a little wet within the rot limit, and new building materials that will fail if even a little water gets in.More than the product difference, the insulation structure and details that prevent moisture from getting into the walls are important tasks for designers. I felt it again.

こちらが二階のシージングボードを室内から見たところ。黒色の染みが一面に・・

This is a view of the sheathing board on the second floor from inside the room. Black stains all over...

犯人はラスを留め付けるための又釘が室内に露出しその先端が結露したから。もちろん又釘は錆びて真っ赤です。

The culprit was that the nails used to fasten the lath were exposed inside the room and condensation formed on the tips. Of course, the nails are rusty and red.

二階の外付けアルミサッシの端部は盛大に漏水痕がありました。窓は壁厚内に引っ込めるべきですね～・・・

There were large signs of water leakage at the edges of the external aluminum sash on the second floor. The windows should be recessed into the wall thickness...

冬場、暖房で暖まった高温高湿の室内空気が天井裏に逃げて、陸屋根の雪でキンキンに冷やされた野地板の裏面で結露します。その繰り返しがこの結露痕。でも12ｍｍの野地板は腐りもせずに屋根上の歩行が可能です。

In winter, the high-temperature, high-humidity indoor air warmed by the heater escapes into the ceiling and condenses on the back of the roof boards, which are cooled by the snow on the flat roof. The condensation marks are the result of this repetition. However, 12mm roof boards can be walked on the roof without rotting.

こちらが当時の新建材であるシージングボード。キャッチフレーズは「省エネで耐震だそうな・・」

This is sheathing board, a new building material at the time. The catchphrase is "Energy-saving and earthquake-resistant..."

最近の製図のお供はFIVE NEW OLDですねえ～

My latest drawing companion is FIVE NEW OLD.

5/17 発寒の家Ⅲ

 5/17（水）の「発寒の家Ⅲ」は水廻りの壁と天井の解体がほぼ完了したので躯体の傷み具合を確認します。防湿シートのない壁内がいかに木材にとって過酷な環境だったかがよく分かりました。お風呂場は0.75坪の初期のユニットバスが使われており土台や柱脚も全く問題なし。作り風呂は大好きですが腰下だけでもハーフユニットにする大切さを実感しました。その一方で室内干しや給湯器置き場だった脱衣所の外壁廻りの痛み方が激しく湿気を壁内に日常的に入れることの怖さを再認識しました。

On May 17th (Wednesday), the demolition of the walls and ceiling around the water area for "Hatsu no Ie III" has almost been completed, so we will check the extent of damage to the frame. It became clear how harsh the environment for wood was inside the walls without moisture-proof sheets. The bathroom is an early unit bath measuring 0.75 tsubo, and there are no problems with the foundation or pillar base. I love making baths, but I realized the importance of making a half-unit even if it's just below the waist. On the other hand, the outer wall of the changing room, which was used for indoor drying and water heater storage, was severely damaged, making me realize once again how dangerous it is to let moisture get inside the wall on a daily basis.

こちらは居間の外壁ですがモルタル下地のバラ板は湿気でボケてボロボロでした。当時の羽柄材は乾燥が不十分なグリーン材も多かったようで、すぐ下のバラ板は何でもないことから、施工時の含水率を下げることの大切さ（乾燥材使用）をあらためて痛感します。

This is the outer wall of the living room, and the loose boards on the mortar base were blurry and crumbling from the humidity. It seems that many of the feathered materials at that time were green materials that were not sufficiently dried, and since the loose board just below was nothing, I realized once again the importance of lowering the moisture content during construction (using dry materials). Masu.

当時のメガネ石に比較的新しいＦＦ式の排気トップを通して使っていました。給湯器の寿命は約10年くらいなので何度か交換するうちにこうなったのだと思います。このメガネ石はコンクリート製なので断熱はありません。壁の中で結露し周囲の木材を腐らせていたことが分かります。こうした状況を見るとあらためて設備管の外壁貫通部分に気密ガスケットが必要なことが分かります。

I was using a relatively new FF type exhaust top through the glasses stone at the time. The lifespan of a water heater is about 10 years, so I think this happened after replacing it several times. This spectacle stone is made of concrete, so there is no insulation. It turns out that condensation was condensing inside the walls and rotting the surrounding wood. Looking at this situation, it becomes clear that an airtight gasket is required for the part of the equipment pipe that penetrates the outside wall.

壁内の湿気によってモルタルの下地である12ｍｍのバラ板が腐ってなくなっていました。

The 12mm loose boards that served as the base for the mortar had rotted and disappeared due to the moisture in the walls.