Latex-modified thinset mortars offer excellent adhesion and water resistance. This makes them a good choice for exterior installations or tiles that are exposed to moisture. These mortars traditionally require the use of bracing or temporary holding devices to prevent the tile from sagging or slipping during installation. Holding devices are effective but can make installation a slow-going process.
A new advanced mortar type, called performance mortar, addresses installation issues related to non-sag and other thinset mortars. These products provide a quick "grab" of tile weighing up to 6 pounds per square foot, thus eliminating the need for bracing. Some performance mortars are formulated with hollow, ceramic microspheres that produce a ball-bearing effect resulting in minimal trowel resistance and less tile-setter fatigue. Performance mortars also require no additives or extra mixing time and may be used with waterproofing membranes.