The purpose of the ELEMENTAL Chile competition, as well as the project later developed in response to the socio-economic and climatic conditions of Valdivia, X Region, Chile, was the design and construction of experimental social housing whose cost, including land and services, would not exceed 7,500 US$ per unit. The units were therefore designed "to grow", being adaptable by owners and making it possible at the same time to achieve higher urban density above local average, to reduce and spread the burden of land costs and urban infrastructure. The project adopts a three-storey
compact typology echoing the local tradition of a “big house”, with 2 units on the ground floor and 4 maisonettes on the first and second floor. The local timber construction tradition, and its social acceptance and knowledge within the context of Valdivia, led us to develop a mixed
construction system, which combines timber frame and concrete to suit the geotechnical and seismic conditions, and at the same time to overcome the economical restrictions and to fulfill the compelling requirements of spatial flexibility in minimal low-cost units.