Our approach to the design of "N10-Eiras" indoor sports facility was determined twofold: on the one hand by the specific characteristics of the existing industrial pavilion in which we ought to insert our solution. On the other hand by the brief, which asked for three main areas: reception; changing rooms and showers; and a party room. One volume was created, organizing the two main areas at both sides of the reception area, which is also where the entrance is located. The new volume thus created occupies the entire width of the existing pavilion, and its own width results from the subtraction of the football field from the pavilion’s total length. The building system defines the materialization of the volume. A porticoed frame made of American pine wood beams and columns creates the basic structure. The infill of this structure, both in the roof as in the walls, is made through the use of MDF boards, assembled in such a way as to perform both structural and formal roles in the overall construction. The raw use of the MDF boards is followed by a straightforward use of white ceramic tiles in the changing rooms and showers, and by the design of the furniture components, which are also made of raw pine wood elements and black lacquered MDF panels. The layout of the illumination devices was designed in order to accomplish an intense and expressive plasticity out of the volume's formal and material characteristics. A tunnel-like element pierces the pavilion's existing wall to announce in the outside the entrance to the facility.