Cob Construction in Italy: Some Lessons from the Past

Abstract

Raw earth is a construction material unknown to most people. Nowadays, raw-earth constructions are an area of growing interest, both for rescuing the heritage and for a rediscovered environmentally friendly building and eco-sustainability material. However, because raw-earth constructions are a forgotten technique, we find problems of a lack of skilled people at all levels in this area, from designers to masons, as well as problems of how to carry out compatible conservation works on earthen heritage. This paper tries to fill the gap for a peculiar historic earthen building technology, namely cob (or bauge), which is present in Macerata in the center of Italy. Results are presented on regaining possession of the material and constructional aspects and their initial structural resources, and guidelines are given on how to improve the manufacturing process to reuse the cob technique for construction and for how to accurately work on it for a compatible and sustainable conservation.

Experimental and FEM Investigation of Cob Walls under Compression

“…Earthen construction can be divided into four main categories: compressed earth block (CEB), rammed earth, adobe, and cob construction. While a lot of studies were published on the mechanical behaviour of rammed earth, CEB, and adobe [7,[21][22][23][24][25][26][27][28][29], very few researchers studied the mechanical properties of cob, which constitutes a diffuse alternative to rammed earth and adobe in specific geographical conditions [21,[30][31][32][33]. In fact, it is estimated that at least 200,000 units are constructed in EU by the cob technique, date back to the first half of the 20th century, the 19th century, the 18th century, and even older [30].…”

“…Concerning their mechanical behaviour, as already stated above, only few works can be found in the literature. In [31], the authors studied the compression and shear behaviour of still moist Italian cob walls (initial properties). However, no information was provided for walls in dried conditions.…”

Effect of Some Additives on Mechanical and Physical Properties of Cob Building in Iraq

“…al. tried to re-usethe Cob technique for construction and for how to accurately work on it for a suitable and sustainable conservation.the results of this study have found a suitable soil for future possible suitable restoring involvement on the investigated case study at Macerata, re-using the same old building technique, which is the most compatible involvement [6]. This work aims to study the effect of some additives on physical properties (watercontent% and thermal conductivity) and mechanical property (compression strength) of Cob.…”

Earth construction: Lessons from the past for future eco-efficient construction

“…The Portuguese technique ''tabique'' [23] is some how similar to wattle and daub. As to the cob technique it involves mixing earth with straw and water to form layer by layer masonry walls [24]. Rammed earth means the compaction of moist earth (stabilized or not) inside a wooden formwork, although nowadays in Europe the steel formworks are replacing the wooden ones.…”