The house is located on an informal neighborhood on the periphery of Mexico City. It’s a small house of 100 m2 for a retired teacher. The limited budget of the client forced us to use the most common and economic materials of the local construction industry. We worked Hand by Hand with the local builders to re-interpret their knowledge on local construction systems. Originally, the project consisted of two twin patio houses within a small and narrow plot, one for the client and the other one for her sister. Once we started the construction, the front house was cancelled and we only did the house for the client in the back of the plot, leaving a big garden in between the garage and the house. Due to the increasing and fast growth of this region, we estimate than in a period of 5 to 7 years, the surrounding lots will develop in a very dense and intrusive way, leaving our house enclosed by a dense informal housing. Because of this characteristic of the immediate context we decided to design an intrusive body of brick with a concrete skeleton that opens to an inner patio to protect the views from the other neighbors to the plot. This patio is the core of the whole Project. We used the volcanic Stone that we found on the terrain to build the foundations, platform, stairs and exterior wall of the house. The two bedrooms are built over a light wooden deck that gives a warm and beautiful wooden ceiling to the main public spaces below. All the service and circulation areas are located along a linear spine, while the living spaces are located in the arms of the house that enclose the patio. This central – open space articulates the living room and dining room and due to the good weather of the region, the patio can act as an extension of both public spaces to have a bigger public area on the ground floor. light plays an important role in this house and it is managed in various ways according to the space.