As mentioned in the October 15 blog, stone tile installations can suffer when exposed to excess moisture in the concrete slabs the tiles are bonded to. Ceramic tile installations can suffer especially if there are systems other than portland cement involved in the installations. These installations involve the use of certain anti-fracture membranes, sound attenuating membranes, and/or any installations not involving the use of portland cement mortars. The first example is the use of cork sound attenuating membranes. These membranes are widely used and when installed properly can achieve the desired level of performance. The issue with excess moisture when dealing with these systems is simple. The adhesive used to laminate these membranes is differing types of adhesives that are easily damaged by excess moisture in concrete slabs. These adhesives are adversely affected by not only direct contact with excessive moisture but are also adversely affected by changes in alkalinity levels in concrete slabs generally brought about by excessive moisture in the slab. Under normal moisture levels, cork underlayments perform well when properly installed on concrete slabs.