In this study, external thermal insulation retrofitting was performed in four complexes of condominiums, constructed in 1971-72, located in a larger conglomerate of condominiums in Yokohama. Through interviews, we analyzed the process of renovation of each complex. The owners’ association of the first complex that underwent the renovation decided to keep a common room open for the visitors to see the effects of the renovation. The knowledge and experience of the preceding renovation were transmitted in this way to encourage the others to adopt the same method, and the following renovations took place as if in a chain reaction.
