Moisture detection in walls trough measurement of temperature

Evaporation flux from wall surfaces can be estimated quantitatively by measuring the temperature which depends in a sensitive way on the evaporation rate.' When the equilibrium condition is reached the temperature of surfaces where evaporation takes place is in fact directly correlated to the evaporation rate and it depends on several concomitant heat exchange processes. On the other hand starting from non-equilibrium initial condition the "dynamic" measurement of wall surface temperature as a function of time allows the evaluation of water content in the surface layers. In the Archaeometry laboratory of "lstituto di Fisica Generale Applicata" we performed some experiments on several plaster samples among the ones most traditionally used. We employed a climatic room where environmental parameters (temperature, RH, ventilation and irradiation) are controlled and cooling effects due to evaporation are investigated by thermography both in steady and unsteady conditions.