The library is located in one of the expansion areas of the city, where the presence of old steamboats and small single-family houses gradually gives way to new replacement architecture. The whole is made up of two clearly differentiated volumes, arranged obliquely. In the interstitial space between both bodies there is the main access. The largest volume is occupied by the general reading room, at ground floor level, while the lower level contains the children's library and storage. The ground floor of the small volume is used as a reading room for newspapers and magazines, while on the lower level there is an assembly room and a lobby with external access, from an English courtyard located on the south side. Both bodies are determined from the cross-section, designed to provide the entire interior space with homogeneous light, by means of large, curved vaults that evoke the city's industrial past.

The central library of Terrassa is located in one of the main territories undergoing city transformation, currently occupied by small single-family homes and old steamboats. The ensemble reinterprets the neighbouring industrial architectures and is inserted as another piece of this architectural catalogue.

The building fronts the Paseo de las Letras, and although it has generous openings that allow cross visions between the exterior and the interior, it is not very accessible around its perimeter. The spaces are discovered in a chain from the access located in the interstice between the two bodies. The larger volume is the one that houses the main reading room on the ground floor, while the smaller one houses the newspaper and magazine reading spaces.

A large lateral English courtyard allows part of the programme to be placed on a lower level, where the children's library, the storeroom and the meeting room are located.

The building has two sections that, analogous to the old factory complexes in the area, broadly define its main geometry. The roof unfolds in curved sections and provides optimal lighting conditions for the work that takes place inside. The patterned order of the structure ends up being confined in two volumes that fit the trapezoidal perimeter of the plot.