Earth, gypsum and cement-based plasters contribution to indoor comfort and health

Abstract

Indoor air quality is important for comfort and health of buildings inhabitants. The use of environmentally friendly building materials is also very important for sustainable and green buildings. In the present study, mechanical characteristics of five mortars were comparably analyzed: two unstabilized earth mortars, one earth-air lime mortar, one cement mortar and other gypsum mortar. The earthen plasters are nowadays commonly applied unpainted. The gypsum plaster system is composed by the base mortar and a finishing layer; it can be applied unpainted or painted. The cement plaster is generally finished with a paint system. Therefore, the adsorption and desorption capacities were assessed for all the plasters and the influence of the paint system was evaluated for the cement and gypsum plasters. Results show that the earth mortar stabilized with air lime presents lower mechanical strength, in comparison to all other mortars, and lower adsorption capacity, similar to the gypsum system. The unstabilized earth plasters present high adsorption capacity, in comparison to the cement and gypsum plasters. The paint system does not have significant influence on the adsorption capacity of the gypsum plaster but reduced that capacity on the cement plaster. These results demonstrate the important contribution that unstabilized earth plasters may provide as passive indoor hygrothermal buffers, in comparison to other plasters.