Stone has been used as a building material for thousands of years. Its aesthetics and sense of permanence have made it popular, especially among builders and architects. Many of the significant buildings throughout history have been constructed of stone. The evolution of stone facades closely parallels the evolution of building construction and technologies. In the past 100 years, stone has been increasingly used as a cladding material in exterior wall systems. The stone cladding panels in recent use can be classified as thin stone cladding that is less than 3 in. thick and thicker stone cladding that typically ranges from 3 to 8 in. thick. Thin stone cladding is often made up of individually supported units with sealant filling the joints between panels while the thicker stone cladding is installed as stacked panels with joints between the units filled with mortar to transfer gravity load. As the mortar ages, common repair approaches include replacing the mortar with new mortar (repointing) or replacing a portion of it with sealant; the sealant is either installed over the deteriorated mortar or installed in the joint after the mortar is ground out to a depth of between ½ and 1 in. (12 to 25 mm). Depending on the cladding system and previous repairs, extreme care is necessary in deciding the appropriate approach. This paper will provide a brief background of the various types of stone cladding systems and stone types used over the past 100 years. In addition, it will present the general behavior and deterioration mechanisms of the joint materials between the stone units, the material characteristics of the stone that affect repair options, and the sensitivity of previous repairs to joint material selection. Understanding these issues is critical in determining an appropriate approach for treating the joints. Finally, it will include case studies involving joint treatments for various cladding systems and cladding materials.