Casa Calvet is situated at 48 Calle Caspe in Barcelona, and consists of a basement, first floor, four stories, and a typically Catalonian, flat terrace on the roof.

According to César Martinell, the textile-fabricators, Sons of Pedro Mártir Calvet, commissioned Antonio Gaudí to design the building, basing their decision on "the guarantee of success and modernity that Gaudí represented", and also perhaps influenced by the affinity of political ideas with Eduard Calvet, who was a militant "Catalanista" during the Solidaritat Catalana.

The date of the project was March, 1898, but the municipal license was not obtained until January of the following year due to the fact that Gaudí's plans were rejected by the municipal architect of the City on the grounds that the building's height would exceed the maximum permitted for the street on which it was to be built. In answer to this, Gaudí returned the plans with a red line drawn across them, cutting the coronation of the facade to the regulation height, and threatening that if he was not allowed to enact his initial plans, the building would end up appearing sharply interrupted. Perhaps thanks to Eduard Calvet, there was no reply to Gaudí's threat, and the construction began according to Gaudí's original ideas.

Despite this problem with the Administration, the property received a prize for the best building finished in 1900 which exhibited major artistic merits. The structure is formed by supporting walls over those which support the iron jalousse columns and beams, on the basement and first floors, and small wooden beams in the rest of the forged works.

The composition of the principal facade, of the formal seats made of arenisc stone from Montjuic, is based on the axes that mark the openings of the balconies. In the central opening of the principal floor, we find a baroque tribune with forged-iron railings and relief representing different species of mushrooms, which Sr. Calvet collected.