Ardex UI 740 Flexbone Tile Underlayment, 215 SF RollThe Ardex UI 740 Flexbone uncoupling system is a high load bearing membrane that provides maximum protection for tile and stone installations. It is ideal for large format tile in high traffic areas and prevents damage to tile and grout joints. Also suitable as a waterproofing membrane. High load bearing uncoupling membrane Ideal for large format tile and stone in heavy traffic areas For use with porcelain, ceramic, quarry and natural stone tiles