Stone has been and continues to be the main construction material for the architecture of the Sagrada Família. This is how Gaudí wanted it, and this is how it has been for more than 130 years. In previous blog posts, we’ve looked at the international provenance of the stone at the Basilica, necessitated by the closing of the quarries on Montjuïc, and we’ve also looked at the work of the stonemasons to add texture, by hand, to the blocks of stone that are giving shape to the Temple. In this article, however, we want to focus on the main textures used at the Temple. Because the importance of these characteristics in a work of stone masonry goes much further than just aesthetic quality. In fact, the finish, what we see when we look at a wall or a sculpture at the Temple, is intimately tied to the way the stone is produced, from extraction at the quarry to when it is put in place.
As we use different pencils when drawing if we want a thicker or much thinner line, the texture from each phase of production of the stone comes from the tools used to work it. So, when working with the raw block of stone, the resulting texture from the first working will be much rougher, less polished. In fact, this first step is called ‘roughing out’ the stone, as the thickest parts are removed from the block and the general shape begins to become visible and be refined.
Once the block of stone has been roughed out, the process varies depending on the finish required for the project. At the Sagrada Família, there are three main types of finishes, used from the very beginning of the works and still valid today. From rougher to more polished, they are:
1. Boasted or droved. This is the roughest texture used at the Temple and the finish stands out 7-8 cm, or 3-4 cm if we want it flatter. This finish is created by opening a block of stone with a mallet and a boaster or wide chisel. This texture is full of sharp points and irregular cavities, making it a highly irregular surface that creates a play of light and shadows. These irregularities highlight the volume and emphasise the more abrupt nature of the stone. We can find it all over the Temple, especially on the outer face of the central tower of Jesus Christ.
2. Coarse punched. In this case, the finish is less marked but still has texture. The stone is worked with a punch that is used to strike the surface in a more or less regular pattern. The result is a punched texture, 5-6 mm thick, similar to punch engraving. At the Temple, we find punched stone on the jambs and frames of many doors and windows.
3. Bush-hammered. This texture gives us more detail, so it has a finer grain. It gets its name from the bush hammer, a mallet with points on both faces. The fineness of the bush-hammering depends on the number of points, which ranges from 16 on the finest end to 4 on the coarsest. We can find bush-hammered stone on inside and outside walls, flooring and larger surfaces, in general.
After the piece has been bush-hammered and completely shaped, now we can move on to the finest finishes. The most common are polishing, pumicing and sanding, with finishes that range from very shiny to completely matte. Their use depends on the type of stone, as not all of them can withstand these finishes. In fact, with sandstones, which is the main type of stone used at the Sagrada Família, only the hardest stones with the finest grain can be polished. The rest must be worked using pumice, which gives us a very fine but matte finish. This texture is most commonly found in the finishes inside the Temple.
So, these are the main textures created by the traditional process of roughing out and finishing stone at the Temple of the Sagrada Família. Of course, as the stone extraction and production industry advances, the roughing out is now a fully mechanised process, which makes the stonemasons’ work much easier. This way, the artisans can concentrate on the details and work the stone depending on the texture the project requires and not how the block has to be removed from the quarry. Stone, however, is still stone, and the stonemasons’ trade is a noble one that goes back centuries, which despite getting a helping hand from technology, still requires precision and delicacy, strength and technique.
