Porosity of tile adhesive and tile grout
Tile adhesive and grout are naturally porous, which allows water to infiltrate through the grout into adhesive layer and also the tile back. Things that should be considered when tiling on exterior areas are as the following.
1. Resistance property of the adhesive when being in contact with water
2. The structure must be strong enough to support the expected load including tiles, adhesive and grout. Terraces should be designed in such a way that there is a slope to allow drainage. In addition, under-tile waterproof system should also be considered before tiling to prevent water leakage onto lower areas.