The three-story office building is located near Monterrey downtown, at one of the commercial points of the city. Most buildings within this area are old houses that were adapted into offices or new buildings that replaced the old constructions.The design of this project started from the necessity to merge and rehabilitate two existing old houses to convert them into an office building. The main idea was to continue the sustainable approach to avoid demolition and reuse of buildings, as well as materials and finishes.The challenge of the design was to connect the two existing houses which had different levels, with a distribution that is limited to the basic spaces of a traditional home, and transforming them avoiding the demolition of walls and important structures.The formal proposal of the building consists in a membrane that surrounds and interweaves both buildings acting as a double skin, from a coating that acts as a ventilated façade.One of the main constraints that found the project was the orientation of the houses that was resolved by implementing shading devices to minimize the direct incidence of sunlight into the interior and to make use of natural lighting. The building exterior materials are mainly recycled and the sun controlled double glazed windows are oriented in a way that allows the interior natural illumination and the best sights of the city, reducing the energy consumption. In addition some materials and fixtures of the old houses were reutilized such as wall coverings, mirror, doors, steel, etc.