The Restoration of the Sala Hipóstila and the bench of Parc Güell

In Parc Güell, the "trencadís" (mosaic made from broken tiles) is one of the fundamental finishing materials and, without a doubt, the most emblematic. But the material it is made from, enameled baked clay, is inadequate for exposure to the elements. The traditional lead varnish is transparent and can be colored with metallic oxides. Because of this transparency, and in order to obtain a vivid color, that stands out above the red of the clay, it is first necessary to cover it with a white clay called "engalba." The process of baking at low temperatures does not achieve fusion between engalba and red clay. When the varnish deteriorates, water penetrates it and the engalba falls off very easily, and the naked face of the red clay appears. In the case of the "trencadís" this problem is accentuated since, when the pieces are cut, the continuity of the varnish-and thus, the protection-is broken.

Lately, the effects of pollution-especially acid rain, which has accelerated this process-have been noticeable. The wear of the enameled baked clay tile is especially critical to modernist architecture and, along with the corrosion of the metal strips embedded in the lime mortar, constitute the main cause of deterioration. In this way, the two elements that permitted the splendor of this architectural period, the polychromatic tiles and the daring forms created using iron inside the ceramic, are the greatest sources of damage. This is an irreversible process that requires difficult and complex solutions. In this first phase, the coating of the vaults and columns of the Sala Hipóstila and the entire surrounding bench have been worked on. The damages were similar in both places, but the restoration was very different in both intensity and difficulty. In the first place, the Sala Hipóstila, although it is also exterior, is more protected than the bench and so the effects of the elements are reduced. For this reason it was in better condition. On the other hand, the coating is basically white, despite the mosaic effect that is produced by varying tones, and the color highlights are limited to Jujol's great rose-windows. The scarce presence of color has simplified the process of replacement.

Previous restorations, which have often been a source of distortion of the original, were few. They were basically concentrated on specific repairs of the "trencadís" on the lintels. The poor quality of these restorations can be seen in the photographs. Similar actions that reduced the variety of white hues are still found on the walls of the main stairway, in the area where no work has been done.

On the bench, these problems are repeated on a greater scale. The bench's exposure, with some faces in the sun and others in the shade and, therefore, with major temperature differences, the effects of ice, pollution and vandalism caused the greater part of the "trencadís" to lose its enamel. The troubling effect of earlier repairs was also notable. Very large parts of the "trencadís" of the bench, especially in the most worn areas, were produced in old restorations made with no historical rigor. These restorations can be easily seen in the photographs taken before the current restoration. Specifically, in the finishing pieces of the upper- and lower-back supports, two models of substitution can be identified, corresponding to two distinct phases: one, in which pieces of uniform colors (white, green and blue) were used; and another, in which the replacement was made using pieces of ceramic from Esparraguera, with a yellow background and various types of green blots. In both cases, the joints of the pieces are perpendicular to the edge and not the bevel, as was the case in the original pieces. Also, many white tiles were taken from the base of the bench, although it was more difficult to detect because of their color.

One of the first tasks performed in the restoration consisted in identifying and documenting the pieces of tile. Various restorations were identified, based on the type of tile used, whether manually or mechanically manufactured, the type of varnish and engalba, the type of support, as well as the method of placement and the type of adhesive material. In addition, a minute photographic study was made of the polychromatic elements. The full length of the bench was photographed, front and back, every 50 centimeters.