The Corner House reformation project is located in a traditional building in the neighbourhood of Malasaña in Madrid. The spatial strategy of the project responds to the advantage given by the corner position, emptying the diagonal direction of the dwelling. This creates an open plan space towards the light corner and allocates all the day/light activities in it, whereas the night/dark ones remain to the sides of this main zone. The idea of clearing that diagonal implies a constructive and structural alteration. The thick bearing walls are replaced by a steel structure based on pillars and beams that, besides, help with the articulation of the different areas and activities to be developed in the house.