Is it not necessary to apply for building confirmation to change the usage of a detached house with 3 floors and less than 200 m2?

^{Review of fire-resistant structural requirements for three-story buildings under 200 square meters.}

Until now, when retail stores, restaurants, guesthouses, shared houses (dormitories), and elderly welfare facilities were to be located on the third floor or higher of a special building listed in Column (i) of Appendix 1 of the Act, the entire building was to be a fire-resistant building. It was necessary to do that.

If a building is to be used for a special building purpose as defined in Column (i) of Appendix 1 of the Building Standards Act on the third floor or higher, it must be a fire-resistant building, which has been a hindrance when changing the building's use.

With this legal revision, buildings with a total floor area of ​​less than 200 square meters and three stories or less are no longer required to be fire-resistant buildings, even if these uses are located on the third floor.

The size for which a building permit application is required for a change of use has been changed from 100 m² or less to 200 m² or less.
This amendment allows most detached houses to be converted to other uses, such as retail stores, restaurants, guesthouses, shared houses (dormitories), or elderly care facilities, without having to submit a building permit application.

According to a survey by the Ministry of Land, Infrastructure, Transport and Tourism, more than 90% of detached houses are three stories or less and 200 square meters or less in size. This legal amendment will allow many detached houses to change their use without requiring a building permit application.

Area distribution of detached housing stock (Materials from the Ministry of Land, Infrastructure, Transport and Tourism's briefing session on the revised Building Standards Act of 2018)

This amendment will allow many detached houses that were previously unable to submit applications for confirmation of change of use due to not having obtained a certificate of inspection to have their use changed.

^{Points to note when amending the law}

The two legal amendments mentioned above will make it possible to change the use of small buildings to special buildings without requiring major construction work or surveys, and without needing to apply for building permits.
However, it's important to understand that just because building permits are no longer required doesn't mean anything goes.
Although regulations concerning fire-resistant buildings have been revised, when changing the use of a building, retroactive compliance with regulations regarding use restrictions and evacuation/smoke exhaust is necessary, and the building must also comply with the Fire Service Act and the Building Standards Act.