This work presents experimental values of Moisture Buffer Value (MBV) obtained with three different samples of building materials, using a non-stationary process of moisture absorption. The tests carried out at the laboratory tried to explore the importance of some of the variables that can interfere in the final results, such as materials themselves, temperature level and the use of finishing coatings. The experimental data obtained at 15°C and 23°C were then analyzed using the second order sorption kinetic model. The application of kinetics models to the experimental results was explored and several parameters were retrieved. A proposal for the use of these parameters is presented and its practical use is discussed.