Vernacular Earthen Buildings from Leiria, Portugal – Material Characterization

In Portugal, a large number of vernacular earthen buildings present an advanced state of degradation. These buildings comprise historical, technological, architectonic, cultural and social recognized values and, therefore, efficient interventions are needed for their conservation. The knowledge of the properties that the materials used in their construction show nowadays is one of the bases to support future interventions. Unstabilized earthen samples were collected from the walls of six earthen buildings located in the region of Leiria, Portugal, built with rammed earth and/or adobe masonry. The samples were characterized by particle size distribution and through XRD, density, capillary absorption, drying, dry abrasion, compressive and tensile flexural strength. Mechanical results of rammed earth were lower than adobe’s, contrary to what was commonly found in other studies, and capillary coefficients of adobe were comparable to lime-stabilized adobe from other regions. A surface protection by compatible renders, respectively, earthen-based and air lime-based, is strongly encouraged to extend the walls durability. Although based on a short sampling, this data gives initial support to future compatible, effective and reversible interventions in Leiria vernacular earthen buildings, contributing to the preservation of this earth-built heritage.