The library building appears as a physics permeability  of the Pereira Henriques Street, which descends from the railway line up to Açucar Street and the Garden of Mitra. It is for this reason that the project is formalized in a geometry that allows the existence of a sunken courtyard in the building, playing with different dimensions, light and views. The visual framing arises as a consequence of the light applied to the rigidity of the concrete form.
The exterior disagreements are linear frameworks from axes or directions, inviting the entry into the place where this twist / geometric irregularity applies.
The fact that the building does not touch the lower level in some parts enables visual relationships with some pre-existing constructions such as the main entrance of the library that is by this very spot, made through a ramp that leads to a travel around inside perimeter of the building, making a circulation in a kind of "U" to enter the building itself, enabling a peripheral view of the entire space. This ramp arises in alignment with the existing opening on the block next to Açucar Street,that is unused until now, but will allow direct access to space in the building.
Thus we have a building that is built around an empty space, a kind of courtyard that does not perform it’s fully functions, it is actually an extension not only of the Mitra garden as well as of the street, entering the intrinsic space of the building. This space is not plan, it goes down, which allows shading games and thereby defining the perimeter of the building in a non-intrusive way. It is also in the "Courtyard" that the fenestrations assume their full significance, since the entire outer perimeter is blind, protecting the library from the noise and pollution that is not consistent with the proposed function
These courtyard will be central in the lighting of spaces as well as the work of the plasticity of a crude volume of concrete, which presence enhances the kinks, directions and axes which identify the function and consequently the experience of the space. Here there is a possibility of occupying a balcony, a result of the readings of axes and directions mentioned above
Inside, the project is organized into functional wings, that in opposite ends are located the two prime areas of a library - children's reading room and adults´ reading room.
The multipurpose room is located at a point near the main entrance allowing easy evacuation of the public for the bar that strategically lies in the outer space. Since this is a space where exist many people flows at once, the corridors which, although relatively large, increase spatial awareness due to the slight twisting of the horizontal walls
For the essential programmatic library features of this scale, administrative area and the deposit area are organized vertically allowing fast and easy connection to each of the wings for the repository of the books (adult and children). The section devoted to children's reading room, is separate from adults’ reading room, in addition the access is made both by the main lobby as a second more direct entry, located in the ward.
Tectonically the building assumes the concrete texture, with mixed walls of concrete and masonry plastered on the inside. The slope of the outside pillars streamlines the space, not giving a monotonous aspect.