Characterisation of the progression of salts in walls of earthen architecture heritage

Abstract Two hundred years (1750–1950) of earthen architecture represents an important period construction in the central region Portugal. Earthen is usually built close to coast or rivers and placed sandy ground. The impact rising damp a general problem efflorescences are common cause damage decay. This was studied building with two types construction, adobe masonry walls formed walls. aim this research characterise conditions for appearance phase transitions thénardite mirabilite, determine how prevent progression salt effects wall support future conservation measures. Laboratory capillarity porosimetry tests dolomitic air lime mortar hygrothermal monitoring were pursued along situ tests. Visual assessment showed that salts depends on composition materials. To understand these differences, all crystalline solid phases analysed by powder X-ray diffraction, interior monitored. An investigation into influence surface water painting sacrificial application crystallisation sodium sulfates concluded also depend wall's composition. Data allowed us conclude inside temperature humidity [relative (RH = 100 p w / ° > 70)] led breakdown fast conversion from mirabilite. Therefore, contact wet atmospheres should be avoided controlled. environmental spaces had results. results contribute understanding pattern decay, as well supporting recommendations conservation, based identification proper their occurrence.