The Nadir Afonso Foundation by Álvaro Siza Vieira in Chaves, Portugal, sits on a terrain located on the right bank of the Tâmega river. The area destined to the building was established in the plan as a rectangle parallel to the riverbed.
The main floor of the foundation building is placed over a concrete platform supported by walls perpendicular to the river, in order to prevent an eventual flood. The height difference between the northwest street layout and the natural terrain is balanced by means of a ramp with a slight slop.
The main access to the foundation platform is made by means of a slight ramp with a slop of 6%, from the sidewalk. Furthermore, two elevators and two staircases have been projected, from the ground, southwest (public access) and northeast (service access, loading and unloading). In a more central positioning, by the access to the exhibition spaces, there is a third staircase designed as an emergency exit.
The internal programmed spaces are conceived longitudinally in three sectors. First, an atrium, a reception, a public elevator, a library, an auditorium with a seating capacity for 100 people, a cloakroom, restrooms, a bookstore and a cafeteria at the southwest top of the building.
Secondly, several exhibition spaces, in the central zone, subdivided into 3 longitudinal wings and including both a permanent exhibition room and an archive (northwest wing), temporary exhibition rooms (central and southeast wings). The exhibition room in the central wing, which can be asymmetrically subdivided into two, has a continuous clerestory allowing both natural and electrical light; the exhibition room in the southeast wing is illuminated by means of a continuous horizontal opening over the river or by coving. The temporary exhibition room doesn’t have general natural light but only an opening over the yard that limits it.
Lastly, the northeast top of the building includes a control and security center, a hoist, a service staircase, a reception and access to the archives (northwest); restrooms, a staff room and administration areas (southeast); a plastic arts room and Nadir Afonso studio (with zenithal light and river view).
In the upper floor, which can be accessed through the control and security center, there is a set of technical spaces (interior and exterior balcony), from which is made easier the access to the skylights and to a second technical space located over the auditorium.
The building is built with apparent structural white concrete walls; the roof is covered almost completely with pebbles, and the top of the skylights and the machine room is covered with zinc plate. The essential interior finishes consist in wood floors, plasterboard on the walls and ceilings and white marble on the water zones. The interior window frames are made of wood and stainless steel; the exterior ones are made of wood and aluminium. The exterior floors are composed of granite on the stairs and the access floor; and white marble on the balconies.