The growth in urban population in Third World countries has been dramatic in the last decades, motivating a very large demand for low-income housing. The offer of affordable housing units produced by the formal construction sector is not inexpensive enough to cover all the demand. This pushes many families into the informal construction of their dwellings, with very negative consequences on the quality of life. This paper shows research oriented to make legally built housing more affordable, by using the concept of progressive development.
