Building of houses facing roads less than 4 m wide[Building Standards Law Of Japan]

Hello everyone! I am Yamaken.(@yama_architect

I usually provide information on architecture and real estate on a daily basis while consulting on city planning.




Relief system road

Japanese law requires that the building site be adjacent to a road that is at least 4 meters wide.Roads are used not only for passing vehicles, but also for securing sunlight and ventilation inside buildings, passing emergency vehicles, and even preventing the spread of fire in buildings.

For these reasons, the Building Standards Act stipulates that roads should be at least 4 m (6 m in snowy areas) and above.

However, in densely built-up areas and castle towns, there are many areas where the road width of 4 m cannot be secured due to the history and formation process of the city.

For this reason, the Building Standards Act provides for the mitigation of roads less than 4 m wide that existed prior to the enforcement of this Act (1952).

By retreating the road boundary, the cost of setback (Demolition of gates and fences) is incurred and the building site is reduced.Also, there are many troubles after purchasing the land. Therefore, it is the right choice to purchase after receiving a thorough explanation from the real estate agent at the time of purchase and understanding.

About reduction of site area

Due to the obligation to withdraw, the site area will be reduced.

See the figure below. For example, a road that is 2 meters wide is a road that requires a set bag, and the site adjacent to this road is 10 meters long.

In this way, Building Standards Law of Japan stipulates that a road width of 4 meters or more must be secured in the future. In addition, some local governments purchase or donate the widened part.

It is considered effective in areas where land rights are complicated and urban areas are dense, such as Japan.

Does setback require removal of fences?

Of course, the setback part must be used for the road.

Therefore, buildings (Gates, fences, and buildings) must be removed from the setback.In many cases, all buried objects will be removed to meet the standards of road construction.