As more and more people live in cities, both great opportunities and major issues arise. In many countries rapid urbanization has led to the creation of economic, cultural and political strongholds, in others it lead to the formation of slums. Cost is one challenge. Global consultancy firm McKinsey & Company estimates that the cost of providing affordable housing to the 330 million households currently living in substandard accommodation is $16 trillion. Sustainability is another. While affordable housing development projects are being implemented, many do not consider the sustainability of such projects. This gap manifests itself in a reduced sense of ownership and community among home buyers, which in turn, can lead to abandonment of homes, defaults on mortgages, decline in brand value for developers, as well as unsafe neighborhoods. Social sustainability in housing is about creating affordable, good-quality, inclusive, secure and healthy communities which are well integrated into the wider urban systems. It takes into consideration cultural values, norms and traditions, as well as lifestyles and behaviors of occupants. To build socially sustainable homes, it is important to understand and plan for complex issues, which are How do we ensure long term sustainability when building new residential communities? often not addressed at the conceptualization of an affordable housing project. Social sustainability connects the design of the physical environment with how the people who live in and use a space relate to each other and function as a community. It is enhanced by development which provides the right infrastructure to support a strong social and cultural life, opportunities for people to get involved, and scope for the place and the community to evolve. ASHA (Affordable and Socially Sustainable Housing Application) tool, developed by IFC, a member of the World Bank Group, provides guidelines and good practice collected from both developed and emerging markets around the world, and aims to facilitate socially sustainable residential projects. The guide is focused on the social aspects of building new housing and the information is evidence-based with an emphasis on solutions. It is a global framework within which a more clearly defined context might be detailed.