According to the International Energy Agency, the energy use in buildings accounts up to 38% of global energy consumption reaching in developed countries the 45% of the energy use in buildings in 2012. A substantial increase in global energy consumption has been recorded in recent years and a reduction of the energy demand for thermal comfort in buildings is mandatory. This reduction can be achieved by the development of new materials to be implemented in building envelopes. Thermal energy storage (TES) is an alternative to save energy and it has been investigated extensively in recent years. The addition of phase change materials (PCM) in a material increases its thermal inertia because PCM are capable to store and release energy as sensible and latent heat, therefore the energy consumption can be reduced. In this study, phase change materials (PCM) are added into a common gypsum matrix (E-35) by three different methods: adding microencapsulated PCM (Micronal® 5001X), making a suspension of the PCM in water, and incorporating the PCM through an impregnation method. RT-21 paraffin waxes PCM were used in the suspension and impregnation formula. Gypsum has two important states during the implementation process: fresh and hardened states. Properties in fresh state define the workability of the material: adherence, consistency, working and setting times, etc. The addition of PCM into the gypsum matrix modifies all these properties so, the aim of the paper is to analyze, compare and evaluate the variability of the properties during fresh state after the inclusion of PCM by three different methods (microencapsulated, suspension and impregnation process).