Yumoto Shimakan is a hot spring inn near the Shima River. The inn is located in Shima Onsen, one of the most popular hot-spring areas in Gunma Prefecture, and many literary figures such as Masuji Ibuse and Osamu Dazai visited the inn. Our job was to plan a new wooden roof over the existing riverside outdoor hot spring bath.
Latticework that lets light in and steam out was installed along the roof that was built to block the line of sight from guestrooms above the outdoor hot spring bath. Although the roof area was about 30 square meters, we were able to avoid having to file an application for building confirmation because most of the latticework was installed onto the ceiling so the roof area was calculated as less than 10 square meters. By installing the minimum required roof-supporting walls and columns, we created a sense of openness for the outdoor hot spring bath while keeping it hidden from the guestrooms.