QLA Interiors recommend the below adhesives and sealents, these have been successfully used and tested with our products however as each application is different we always recommend a patch test before applying to check for suitability (Adhesives also need to be applied onto a sound surface with no loose particles or dust on the surface as per the product installation guidelines). When natural materials are used externally they will be subject to UV/ weathering and therefore future colour change. Sealants can assist in resisting this change but will need to be installed/reinstalled as per the product guidelines. Stone is  naturally porus so we strongly recommend protecting the stone with a natural stone sealant against oils, grease and limescale.