After submitting the tiles to the exterior climate conditions (aging), the differences in SRI levels for the clay and concrete tiles were calculated 67% of the concrete tiles remained stable, whereas none of the clay tiles were within this range. 50% of the clay materials registered a moderate degradation of their SRI levels. Within the materials which show strong degradation are 50% of the clay and 33% of the concrete materials evaluated. The SRI values decrease in an average 30% in the case of clay tiles and 23% in the case of the concrete tiles. (Fig. 3a)