The long-lasting performance of a tile job depends on the substrate it rests on. Most tile callbacks have to do with cracking or loose tiles caused by movement of the substrate, and usually this is the result of an inadequate substrate rather than undersized framing or settlement in a house. Wood and drywall are not good tile substrates. The best options are a mortar base, a cementitious backerboard, or a rubber cleavage membrane. Here's a look at the different options. Mortar Bases Of all the substrate options, a two-coat mortar base (scratch coat and brown coat) is the strongest and most durable. Use a mortar base under tile in wet locations and on high-traffic floors where durability is most needed. A mortar base