Finishing techniques for exposed brickwork in 12th to 15th-century Tuscan architecture

An our research on Siena and Central Tuscany has enabled us to formulate hypotheses on the evolution, through time, of the different finishing techniques for exposed brick surfaces. We identified three main phases. 1. The first one dates back to between the end of the 12th and the second half of the 13th century. The most significant building is the cathedral of Siena: the original brick walls of the Romanesque church are finished with diagonal or herringbone hatching. The hatching was executed with a small flat-bladed axe, working the fired bricks one by one before laying. This technique links Siena cathedral to the Romanesque and early Gothic brick churches of the Po Valley. 2. A new finishing technique, one of the most refined in Europe, was introduced towards the end of the 13th century. The most significant example is the first floor façade of the Town Hall of Siena. All the building work is in herringbone hatched rubbed bricks. Moreover, the first floor was planned to receive a red colouring directly spread on bricks, enriched, in the decorative features, with golden yellow and light blue. In order to obtain a hatching with accurate parallel lines, they could not have used an axe as in the previous phase. They might have used a thin flat bladed percussion tool, the strokes of which can be recognized. 3. The use of hatching in Siena did not continue beyond the second half of the 14th century, and this trend seems common to other Tuscan towns. However, the taste for giving exposed brickwork a refined finish had not been exhausted. The 15th-century façades of many gothic and renaissance buildings were entirely realized with rubbed bricks. According to Leon Battista Alberti the rubbing was done after the firing and before the laying, brick by brick, with the same technique as in the preceding century.