The competition specified a single family urban house, in a 10 x 30 metre plot between 3 metre high boundary walls. The 130 m2 house had to be 100% accessible, and had to consider energy efficient strategies. In order to respect the full accessibility, the project is developed in one level, looking for a strong bond between the building and the ground. Level differences are minimum, and simple details such as small ramps or window frames hidden in the floor, strengthen the idea of a unique level of living.In the house, public/private spaces in the everyday living are defined in a horizontal sequence. Schematically, three areas contain the architectural program. At the front: the social spaces.In the middle: bathrooms, barbecue, storage space and the inner yard (‘green house’).At the back: the private spaces (bedrooms).The inner yard (‘green house'), with its mobile glass roof, articulates the house allowing spaces to expand, at the same time as it is the energy resource of the house. This yard accumulates heat in the winter and allows proper ventilation in the summer. In the winter, the house expands its social space into this yard, allowing a bigger house in the cold times of the year.The design looks for simple and luminous interiors, with a small amount of materials in use, and a strong visual relation with the garden.The plot’s bounding walls are treated in common brick and painted white, becoming the main texture of the house. The concrete slab is exposed, the floors are made in monolithic, and the limits between exterior and interior are treated with perforated anodized aluminum shutters. These shutters work as security device and solar protection at the same time.The materials selected for the house, asure a correct aging of the building and low maintenance costs.