The Mazorel residence is located in the municipality of CREST in the Drôme (26); this complex comprises 48 dwellings spread over two buildings, each comprising 24 dwellings. This heritage has already been the subject of an ambitious rehabilitation in the 90s with the creation of verandas and thermal facades. Today, the group is aging and knows many disorders (infiltrations, dilapidated facades...). The purpose of the operation consists in the thermal rehabilitation of the 48 housing units concerned, allowing to achieve a better energy performance and a reduction in charges for tenants.