A.D. BUENO, P.C. PHILIPPI, R. LAMBERTS Federal University of Santa Catarina, Brazil

Moisture is responsible for mould growth and affects the mechanical resistance, aesthetics and durability of building materials. Permeability to water vapour and heat transfer are dependent on moisture content, modifying the energy balance of the building, thermal comfort and health conditions of its inhabitants. The paper discusses the influence of water vapour sorption processes on the thermal behaviour of an hygroscopic building material. Sorption isotherms were obtained experimentally from samples of a cement and lime mortar used as rendering, to give results by empirical modelling. A simple, lumped, mathematical model is used to describe the temperature evolution of the sample when subjected to daily fluctuations of temperature and relative humidity. Results show the influence of water vapour sorption on the temperature evolution and energy balances.