The main atrium boasts a granite staircase with two flights of stairs and handrails, on the north side, "set along the axis of the building, in a symmetrical succession of the reception areas. The elevations follow the classical style, alternating areas of masonry and stucco, topped off with a continuous cornice. At the centre of the north and south elevations, the pediments on pillars mark the main accesses; the eastern and western elevations have an extensive number of identical spans, organized in two planes that link the ground floor to the mezzanine, and the 3rd and 4th floors" (cf. Document prepared in June 2004 by António Portugal & Manuel Maria Reis, arquitetos e associados, Lda.).
A bronze bust of Francisco Gomes Teixeira, 1st Rector of the University of Porto, can be seen on the landing. It dates from 1914 and was done by António Teixeira Lopes (1866-1942), a sculptor from Gaia who was taught by António Soares dos Reis (1847-1889).
The side walls at the top of the staircase are decorated with two oil paintings by José Maria Veloso Salgado (1864-1945), representing "Mathematics" and "Physical and Natural Sciences". The paintings date back to 1917 and are signed. The female and male allegories, on thrones, stairs and porticos, represent in the first canvas Mathematics, Algebra, Geometry and Calculus and in the second Engineering, Physics, Chemistry and Biology, in an academic type painting typical of the end of the century art.
In 1925, José Maria Veloso Salgado, a painter of the second generation of naturalists and teacher at the Lisbon School of Fine Arts, produced another series of works for the University of Porto, consisting of two paintings for the Conference Hall of the Faculty of Sciences, subject to the themes "Pedro Nunes teaching Mathematics" and "Brotero giving a Botany lesson". These paintings, lost in the fire on 20 April 1974, are part of the famous cycles of historical and decorative painting of the artist, done under exceptional circumstances to decorate monuments of the main Portuguese cities, such as the Main Hall of the Trade Court (1898-1904), Palácio da Bolsa, in Porto, the Faculty of Medicine of the University of Lisbon (Campo de Santana), the Military Museum and the Parliament in Lisbon. Veloso Salgado also painted genre, landscapes and portraits, experimented in Symbolist painting , and was influenced by the French avant-garde group, Nabis de Bonnard.