Salt contamination in heritage stone affects handheld moisture meter measurements on-site. This poses a problem when the readings indicate erroneously higher levels of moisture than actually present. For decision making with regards to moisture prevention treatment it is therefore crucial to distinguish between actual dampness and the hygroscopic action of salts. This study investigated the effect on moisture meter readings of both increased conductivity of pore water and the increased water retention caused by the presence of sodium chloride (NaCl) in artificially contaminated Portland limestone samples. The influence of NaCl contamination on selected handheld moisture meters was quantified. As a result, the paper proposes that under certain circumstances moisture meters could be used to diagnose, reliably, both moisture and salt problems in heritage stone.
limestone
,non-destructive testing
,stone heritage
,sodium chloride
