This article is part of the project "Integración en fachada continua", winner of 1er Concurso de Arquitectura e Integración Social - Comunidades de Ingresos Diversos (2009), organized by the Department of Housing and Urban Development, the Faculty of Architecture and Urbanism of Universidad de Chile, and the Faculty of Architecture, Design, and Urban Studies of Pontificia Universidad Católica de Chile. In this article, we cover conceptual aspects related to social segregation and the urban characteristics that intensify it in Santiago. Then, we explain how our proposal provides guidelines to generate social integration, using Santiago's small housing estates as historical reference and model. Lastly, we discuss the social, urban-architectural, and economic aspects of the project, describing how urban borders make social integration possible, as well as the benefts and risks that different socio-economic groups face when sharing the same living spaces and urban context.