In Lima, informal settlements emerge from the construction of straw houses in the desert under poverty and precarious conditions. However, after seven decades of existence, they have transformed into relatively integrated neighborhoods in the city, with considerable level of development. This article describes how an urban fabric emerges within inverted planning processes, from large to small scales, from the city to the house (urbanization-division-consruction), being this inversion the engine of its development. Straw houses, the only material that enables communities to settle in the territory, apart from offering shelter, have become a strategy for city making. Housing is either a workshop or a store, a contribution to the urban fabric; it also changes its functions according to the needs of dwellers; housing expands as the neighborhood densifi es, transforming its typology (from house to group home) or nature (rural to urban) when the settlement changes from village to neighborhood. The house expands as the city grows; both elements transform each other, giving dynamism to urban fabric, as well as ability to evolve.