lorenab23 Jul 15, 2012:

Hello Dinorah Infill Housing, in the US (in general), means constructing houses in empty lots owned by the county for mid and low income families. The program allows profit and non-profit organizations to build on these lots. I do not know if there is a coined phrase (I haven't been able to find one) but it would be something like programa de urbanización en terrenos baldíos

Infill in its broadest meaning is material that fills in an otherwise unoccupied space. The term is commonly used in association with construction techniques such as wattle and daub, and civil engineering activities such as land reclamation.
Urban infill
In the urban planning and development industries, infill is the use of land within a built-up area for further construction, especially as part of a community redevelopment or growth management program or as part of smart growth. It focuses on the reuse and repositioning of obsolete or underutilized buildings and sites. This type of development is essential to renewing blighted neighborhoods and knitting them back together with more prosperous communities.
http://en.wikipedia.org/wiki/Infill