“Kizami” is the process of making a hole in a timber, making a cutout, and transforming wood from a simple “material” into a “member” constituting a building. This process with hands is called hand-carving by carpenters, “te-kizami”. In contrast, when mechanical processing is carried out in an automated factory rather than by human workers, this is known as “precutting”. Currently, more than 90% of the houses built by the wooden framework construction method are constructed via precutting.

In the case of carving, air dried lumbers are used as the structural material. A lumber has its own nature. The carpenter examines the nature of the lumber and puts it to the right place. It is also possible to identify the peculiarities of the wood and perform processing that cannot be done by precutting.

A penetrating member, called “Nuki”, is a horizontal member that passes through a pillar by penetrating. The penetrating member plays the role of the undercoating for the earth wall, and prevents the house from breaking down. Since the framework built by a penetration structure theory has high deformation performance, even if the building is greatly inclined when exposed to external forces such as earthquakes, it will not collapse completely. This provides time for evacuation in case of emergency, and protects the lives of the residents.

Earth wall, called “tsuchi-kabe”, is literally the wall made of earth. Mud is painted on a mesh-shaped bamboo net, called “Takekomai”, which is stretched between the pillars, to form the earth wall. Takekomai bamboo net is made of many cracked and thin bamboo, called “shinodake”. When Takekomai is being knitted, the bamboo net and penetrate members are entwined with straw ropes. How to make the mud for the earth wall is to mix water and straw sash with clay-based soil. And leave the soil until the straw ferments and the mud has enough stickiness. And it takes 1 or 2 months to dry for the painted mud of the bamboo net.

“Itakura” is a construction method in which thick and bold wooden plates are fitted between pillars and columns to make walls, floors and roofs as earthquake resistant elements. The “Itakura” construction method has been used frequently to build a shrine and a granary since many years ago. It has long been a method of setting up buildings to protect what is important to us, and long been necessary for our Japanese faith and living. That method has been of course used for a long time as a construction method for building a house.

A house built by the traditional construction method can be reused for relocating or diversion, because the house can be dismantled by the reverse procedure of the building. In case of field rebuilding and relocation, almost all materials can be reused by exchanging only the damaged part of the wood and by remaking the soil. Also, trees and paper can be used as fuel, so even if the materials can not be reused, they are never discarded. The materials used for traditional construction method, which are wood, soil, stone and paper, will all return to the earth. The traditional construction method is very friendly to the environment.

Moisture greatly affects the life of a building. Most of the materials used in the traditional construction method can adjust the humidity by themselves by drawing in or letting out moisture. Although moisture rusts metal, moisture is not much a problem for wood. Dry wood will not decay and last longer. In order to protect the material from moisture, put out the eaves deeply to avoid rain, or stretch the waist wall at the part wet by rain.

When the house is damaged by an earthquake or the like, if you can apply partial repair, you will soon reuse the house. It is important to acquire “Shinkabe-zukuri” wall building style. You can see the structural materials of columns and beams, and can easily find damaged parts in the house. On the contrary, you cannot see the structural materials in “Ookabe-zukuri” wall building style. Even if the structural material is damaged, you cannot easily find out the place. Therefore, when you try to confirm damages in the house, the whole building construction is required.

A Building requires energy ① to build ② to use ③ to break, and ④ to reuse. When building a wooden house, the energy required is about one-third of the reinforced concrete structure and about a half of the steel frame.

When dismantling wooden houses, if you burn the dismantled waste materials, nothing will remain except the soil. Using the waste materials as fuel is not so unusual. Wooden houses built by traditional construction methods can be reused if they are carefully dismantled. Even if you disassemble or reuse the house, only a small amount of energy is needed. On the other hand, the iron recycling consumes enormous amount of electricity and water. The concrete elements should be crushed into pieces for recycling or reclamation. Moreover, we have to prepare the crushing facility and the landfill sites.

The wooden shaft assembly method used in the traditional construction method has the characteristic that the frame itself has strength, and apertures can be installed in many places. When you open many apertures, the wind flows in and out the house. On the contrary, in the construction method that relies on the wall, the position and size of the aperture are quite limited.

The structure made by the traditional wooden shaft assembly method is the design itself. When you enter an old private house, you will look up the ceiling, and be fascinated by a roof truss structure arranged in an orderly manner and a powerful beam structure. In the modern construction method, the ceiling is covered and the wall hides the structure with an “Ookabe” wall building style, but the traditional construction method shows the beauty without hiding the structure.

There are also many sights where the function expresses the design such as the depth of the eaves and the lattice of the window.