Obrero Mundial 144 is a building of 14 apartments located between two streets: the one that gives it his name and Viaducto Miguel Aleman with fronts on both roads. The final volume starts of two premises: first, aims to break the frontal continuity generated by the facades of the buildings in Viaducto, and the second, wich is to create housing with dual orientation. The project is set to be separated from the eastern boundaries of its ground creating a yard that visually connects both streets, Viaducto and Obrero, and generates a third facade on the volume. The building structure is solved with load-bearing walls distibuted at every three meters arranged lengthwise and a concrete core transversely which provides rigidity to the volume. This structural arrangement is the one that sets the interior spaces of the apartments, leaving the service area adjoining to the circulations core, wich help us to optimize the disposition of all of the housing facilities. The design on the east facade is based on a grid of 20x40 centimeters that responds to a module generated from the sizes of the chosen material: a black fluted block, wich fulfills several functions at once: structurals, economics and aesthetics. This grid its interrupted by concrete slabs and vertical drillings intercalated at every level. Then the block is desployed into the main facades to create independent balconies at every space of the departments, wich black color and fluted texture gets to be accentuated by contrast with the vegetation disposed at every balconie.