— Delirious New York Diary

千葉県多古町の古民家改修 その4. 基礎補修と補強 4. Fixing and reinforcement of base structure

一間につき一本の大引。床支持部材が現在の一般住宅より少ないため建物の歪みや床の不安定さにつながっている。 One piece of header joist per room. The number of the floor structure is few compared to today’s houses, therefore the distortion of the house/ room, floor shakiness is obvious.


One of the problem of this building was the lack of essential structure elements at the foundation parts.  As I have mentioned, “roof” structure is overly massive in order to support heavy reed roofing.  However, the foundation part has much less structural element–the number of header joist is just a single piece for a room, therefore the floor was cushy and shaking when I waled in the rooms.



Another major issue is also about the structural issue, as some parts of the building are sunken without maintaining a horizontality.  The first step was to remove all the base structure of the floor area in order to jack-up sunken parts.  After that, structure elements were added to keep horizontality–footings, infills to close the gaps.

ジャッキアップによる傾き補正。既存床構造を取り払った後、歪みや傾きを補正するためにジャッキアップし、束石などを追加・変更して水平出しする。 Jack-up the structure in order to achieve horizontality of the building. The gaps derived from the jack-up operation are filled by footings or other materials.


Two header joists are added for each room–achieving three pieces per room.  As the joists are added, posts and footings are also added; therefore floor joists pieces are more securely fixed to the header joists to support the floor surfaces better; as a result, uncomfortable vibration and shake of the building is eased.

Also, the gallery hallway going around the living rooms is fixed more securely to the main structure in order to prevent from the shaking of the flimsy floor.

一部の束石上土台を入れ替えている。 床下は乾いており、木材の傷みはそれほどない。 Some foundation pieces are replaced, but basically wooden pieces are in fine condition because of the dryness of the underfloor area.

下屋を支える柱の束石変更。押入れ部分で柱の傷みには目をつぶっている。ただ、建物の沈み込みを防ぐため基礎部は補強として入れ替えている。 The foundation part of the additional storage space is renewed. Although it is not so important as a space, the foundation is strengthened in order not to make the building sunk at this part.

大引の追加。 Added header joists.

根太の入れ替え。大引の追加後、根太を加えていく。大引が増えたためにしっかりと根太が固定され、断熱材も入れやすい。 Floor joists are added on the header joists. Now those floor joists are securely fixed to the header joists, so that the floor will be solid.

床下の囲炉裏跡。古くはここに囲炉裏があったようだ。この部分の野地板は切り欠かれていたため、畳がさらに沈み込んだ。大引を追加するために撤去した。 Old fireplace. It was no longer used once tatami mat were placed on top. It was removed for placing header joists.

年代物のジャッキ。現役である。 Old jack up instrument–it is still in use!


Submit comment


Spam Protection by WP-SpamFree