Alveolar erosion in the Tower of Breny (Castellgalí)

The sandstone of marine origin is the most common type of rock in constructions in the south-eastern part of the Bages where it outcrops, from the small barracks and walls in old vineyards to the monumental buildings as the cathedral of the Seu in Manresa. As a result of its calm sedimentation in horizontal layers, sandstones trend of to break into rectangular shapes. Therefore, they’re useful in construction.

The sandstone is made of consolidated with calcareous concrete, very small sand particles. However, according to its content in salt impurities, the sandstone is sensible to progressive degradation by the phenomenon named haloclasia that kicks off the alveolar erosion. The result is a beautiful art craft with a bit of Baroque, Dalinian and Modernist inspiration on the rock surface.

The oldest dated building in the district of Bages is the basement of the Tower of Breny, a 3rd century Roman mausoleum that is located besides the join of the rivers Cardener and Llobregat, in the municipality of Castellgalí. The Tower of Breny was made of large blocks of sandstone that were obtained from a nearby quarry. This great Roman funerary monument was preserved until the 18th century. The stupefaction that that construction on the way to Manresa caused to people originated the nickname of Torre dels Dimonis (= Tower of the Demons). But at the beginning of the 19th century, a house was attached to it and, in 1870, at the time of the industrial revolution, it was dismantled to use the blocks in the construction of a dump on the river Llobregat. Only the basement of the Tower of Breny remained, which has been standing open in the air for 1700 years.

The 1st image shows the most intensely affected by alveolar erosion rock blocks in the Tower of Breny, displaying ​​the slow though unstoppable decomposition rate of the rock.

[fotos Jordi Badia]