The stairs of the apartment collapsed and died. Is the nail corroded around the rust?

This month, in an accident in an apartment in Hachioji, Tokyo, a part of the stairs collapsed and a woman in her 50s died, and the nail used for the connection with the landing was rusted and the wood around it was corroded. Was found by interviewing the investigators.

The Metropolitan Police Department is investigating the details of the fact that the use of wood for the external stairs of an apartment is prohibited by law in principle.

On the 17th of this month, a part of the stairs leading to the 2nd floor suddenly collapsed in an apartment in Minamishincho, Hachioji City, and Satomi Ote (58), who lives on the 3rd floor, fell down about 2 meters and died.

According to the Metropolitan Police Department, the stairs are made of iron, but the landing between the 1st and 2nd floors and the corridor on the 2nd floor are made of wood, and they are connected to the stairs with nails.

Of these, two nails used for the connection with the landing were rusted, and the wood around them was corroded, according to an interview with investigators.

According to the Ministry of Land, Infrastructure, Transport and Tourism, the use of wood for the external stairs of an apartment is basically prohibited by the Building Standards Law.

Also, according to the people concerned, the use of wood was not expected at the design stage of the apartment, so the Metropolitan Police Department is investigating the detailed history of the construction at that time.

First-class architect familiar with defective houses "There can be no wood on the outer stairs"

Regarding this accident, Teruyoshi Taoka, a first-class architect and vice president of the NPO "Architecture G Men's Association" who is familiar with problems such as defective housing, said, "Because the outer stairs are exposed outdoors, it is made of wood. In this case, rainwater soaks in and the tree rots, which is very dangerous. Especially when it is stopped with a nail, water adheres to the iron and the surrounding trees tend to rot. Normally, wood is used for the outer stairs like this time. It's impossible, and I don't know why such work was done. It's a problem not only for the work itself, but also for not being able to check whether it was done properly according to the design drawing. "