Alejandro Aravena. Elemental. Housing cores: a half-house on the ground floor and a two storey apartment above. The empty slot between the white cores are meantto be built into, shown here in a yellow example. Elemental, the Chilean architectural practice of Alejandro Aravena, has just won an award for a 70-unit housing project in Santa Catarina near Monterrey, Mexico.  Using government funding the expensive part of each house is built first: bathrooms, kitchen, stairs, party walls and roof.  This is the first half.  The second half is eventually built into the space between these cores.  Visual cohesion comes from a continuous roof over each set of units, and the placement and rhythm of the first halves.  There are 70 units on .6 ha; the area is middle class, not a slum, and half the project will be self-built.
 
Similar Elemental projects have been built in Chile, with less money and for poorer people.  It is a case of putting whatever funds are available where they are most useful, and leaving the rest to individuals who have some building skills and often innovative ways of occupying space, but not the wherewithal to build  a safe structure, a kitchen and bathroom, and then connect them to the utilities infrastructure.  Elemental SA is in a partnership with COPEC, a Chilean Oil Company to design projects with social impact through 'the development of complex initiatives'.  To get projects such as these in place requires more than a brilliant idea, it requires partners at all levels of urban development.  The city is their workshop.  

Formally built social housing all over the world is a landscape of regimentation; informal barrios and slums all over the world are landscapes of desperate invention.  Elemental's model allows the best from both: safe building standards and people's participation in their own dwellings.