Features

The 2×4 method originated in North America. Its defining feature is the use of 2-inch by 4-inch lumber for the structure, so that the walls themselves become structural—giving the building excellent resistance to earthquakes and other movement. Because insulation is easy to fit inside the walls, the method achieves high insulation and airtightness, making it possible to build energy-efficient homes. The 2×4 method also allows components to be prefabricated, which shortens the construction period. After the floor framing is complete, the weather is checked in advance and the home is built one floor at a time—first floor, second floor, then roof. Because the structure is easy to protect during construction, another advantage is a reduced risk of the vital framework getting wet from rain. On the other hand, the method uses about 1.5 times more lumber than conventional construction, so costs can be higher. Cosmo Kensetsu keeps costs down through its in-house carpenters and its own factory. Conventional construction is a traditional Japanese building technique. Because the structure is created by assembling wooden members, it offers a high degree of freedom in floor plans and is relatively easy to renovate later. However, in exchange for this flexibility, construction requires advanced skill and time, and costs tend to be higher. It is also harder to protect the structure during assembly, so the frame can be struck by rain and absorb water.

2×4工法（枠組み壁工法）

Surface Joining (2×4 Method)

The method adopted by Cosmo Kensetsu.
・The structure is wood, using 2×4-inch lumber.
・ No columns are used at all; structural plywood is nailed to frame members to unify the floor, walls, and roof into a single body.
・ Construction is nail-based, and with fewer types of standardized materials, the work is highly efficient.

コスモ建設が採用する工法。
・構造体は木材。2×4インチサイズの角材を使用。
・ 柱を一切使わず、枠材に構造用合板を釘で固定、床・壁・屋根を一体化させる。
・ 釘打ちが基本で、規格材の種類が少ないので施工が効率的。

2×4工法は北米発祥の建築方法です。最大の特徴は、構造体に2インチ×4インチの木材を使用し、壁自体が構造体となる点にあり、地震などの揺れに対して優れた耐震性を持ちます。また、壁の中に断熱材を入れやすいため、高い断熱性・気密性を実現し、エネルギー効率の良い住宅を建てることが可能です。 また、2×4工法は部材の事前加工が行えるため、施工期間が短縮できます。床組みの施工後、天候を事前に確認し１階部分、２階部分、屋根部分と、１フロアごとに施工します。養生がしやすいため、大切な骨組みを雨で濡らすリスクを減らして施工できるのもメリットです。 一方で、使用する木材が在来工法に比べて約1.5倍多くなるため、コストが割高になることがあります。コスモ建設では、直営大工と自社工場により、コストを削減して対応しております。 在来工法は日本の伝統的な建築技術であり、木材を組み合わせて構造を作るため、間取りの自由度が高く、後からのリフォームも比較的容易です。しかし、その柔軟性の反面、施工には高度な技術と時間が必要であり、コストが高くなる傾向があります。また、建て込み最中の養生が難しく、雨に打たれて水を含んでしまう事があります。

在来工法（木造軸組み工法）

Conventional Construction (Post-and-Beam Wood Framing)

・ The structure is wood, supporting loads through a framework of columns, beams, and diagonal braces.
・In addition to load-bearing walls formed by diagonal braces, methods that use structural plywood to support loads across a surface are becoming more common.
・It falls broadly into two types: “shinkabe,” which leaves columns and beams exposed, and “ōkabe,” which covers them with finishing materials.

コスモ建設が採用する工法。
・構造体は木材。2×4インチサイズの角材を使用。
・ 柱を一切使わず、枠材に構造用合板を釘で固定、床・壁・屋根を一体化させる。
・ 釘打ちが基本で、規格材の種類が少ないので施工が効率的。