The main objective of this research is to elaborate a mortar based on lime (L), pozzolana (PZ) and polypropylene fibers (PP) to restore and renovate the stone constructions while maintaining their initial comfort. Unlike the new buildings, in rehabilitation, we have to deal with the existing ones. For this purpose, mortars samples from an old building, chosen as cases of study, were taken and chemically analyzed in order to reproduce their equivalent mortars. Three different mortars were made and studied. A lime based mortar (M1), lime-pozzolana based mortar (M2) and lime-pozzolana based mortar with polypropylene fibers (M3). In order to preserve the thermal comfort offered by the old building, the thermal conductivity and the mechanical proprieties were studied. The adhesion of each mortar was also tested on several support types (concrete, concrete block, brick and natural stone). Finally, the three studied mortars were applied on the facade of the chosen building. The results are satisfactory on both levels aesthetic and adhesion. The incorporation of polypropylene fibers was more promising regarding thermal comfort. Moreover, their use lightened the matrix and improved the tensile strength.