Homes and their inhabitants represent a legacy that gives life to the city. This contextual heritage, which is fragile in Latin American cities, needs instruments that help with decision making. This paper analyzes residential heritage sustainability indicators using a unique complex preservationist framework: intermediary cities in the Buenos Aires Province. To do it, this research explores sociomaterial, architectural, and protectionist factors in two cities (Mar del Plata and Tandil) that are pertinent because of their historical evolution within a costal-mediterranean contrast framework. From a principally qualitative approach, the paper formulates and evaluates indicators that look towards a long-term residential safeguarding dynamic.