A remodel of a previously built house, it was redesigned in 1904 by Gaudí (but the actual construction works hadn’t begun at this point) and has been refurbished several times since.

Gaudí's assistants Domènec Sugrañes i Gras, Josep Canaleta and Joan Rubió also contributed to the renovation project.

The local name for the building is Casa dels ossos (House of Bones), as it has a visceral, skeletal organic quality.

The design of the house made the home undesirable to buyers but the Batlló family decided to buy the place due to its centralized location.

[5] In 1904, Josep Batlló hired Gaudí to design his home; at first his plans were to tear down the building and construct a completely new house.

Due to the building's location and the beauty of the facilities being rented, the rooms of Casa Batlló were in very high demand and hosted many important events for the city.

The local name for the building is Casa dels ossos (House of Bones), as it has a visceral, skeletal organic quality.

Much of the façade is decorated with a mosaic made of broken ceramic tiles (trencadís) that starts in shades of golden orange moving into greenish blues.

The noble floor is accessed through a private entrance hall that uses skylights resembling tortoise shells and vaulted walls in curving shapes.

On the Passeig de Gracia side is Batlló's study, a dining room, and a secluded spot for courting couples, decorated with a mushroom-shaped fireplace.

In 2002, as part of the celebration of the International Year of Gaudí, the house opened its doors to the public and people were allowed to visit the noble floor.

Two years later, in celebration of the one hundredth anniversary of the beginning of work on Casa Batlló, the fifth floor was restored and the house extended its visit to the loft and the well.

The top of the building is a crown, like a huge gable, which is at the same level as the roof and helps to conceal the room where there used to be water tanks.

The roof's arched profile recalls the spine of a dragon with ceramic tiles for scales, and a small triangular window towards the right of the structure simulates the eye.

The tower is decorated with monograms of Jesus (JHS), Maria (M with the ducal crown) and Joseph (JHP), made of ceramic pieces that stand out golden on the green background that covers the façade.

These symbols show the deep religiosity of Gaudí, who was inspired by the contemporaneous construction of his basilica[13] to choose the theme of the holy family.

[14] The central part of the façade evokes the surface of a lake with water lilies, reminiscent of Monet's Nymphéas, with gentle ripples and reflections caused by the glass and ceramic mosaic.

[3] It is a great undulating surface covered with plaster fragments of colored glass discs combined with 330 rounds of polychrome pottery.

[15] Finally, above the central part of the façade is a smaller balcony, also iron, with a different exterior aesthetic, closer to a local type of lily.

[2] In front of the large windows, as if they were pillars that support the complex stone structure, there are six fine columns that seem to simulate the bones of a limb, with an apparent central articulation; in fact, this is a floral decoration.

The rounded shapes of the gaps and the lip-like edges carved into the stone surrounding them create a semblance of a fully open mouth, for which the Casa Batlló has been nicknamed the "house of yawns".