HYAN Renovates 1970s Timber House into Green Sandwich House in Hayama

HYAN, a Japanese architectural firm, has finalized the Green Sandwich House, a renovation of a timber residence from the 1970s situated in Hayama, Kanagawa, Japan. Instead of tearing down the aging property, the studio opted to preserve it, converting it into a dwelling and workspace for its founders. Constructed in the late 1970s during the establishment of a hillside residential area near Hayama's former imperial villa, the house is part of Japan's pre-1981 seismic-code era. Completed in 2025, the renovation spans 271 square meters and was overseen by Miwa Negoro, with contributions from lead architect Anna Naganuma, design architect Shohei Hasegawa, and interior designer Haruka Shoji. Deguchi Tategu-ten served as the general contractor, and Katsuhiro Aoki captured the project's photographs. The architects emphasized their commitment to sustainable architecture by choosing to retain the existing structure.