What causes grout cracking?
There are several possible reasons for cracking grout: 1. A flexible substrate (plywood, etc.) 2. Poor installation; tile not bonded, resulting in loose tile. 3. A non-sanded grout was used with the grout joints too wide. When the grout shrunk, the only possible thing it could do is crack. 4. The grout joint was not completely filled during installation, leaving voids on the surface. 5. In a large floor installation, where the grout crack is isolated in specific areas, it is usually caused by the lack of expansion joints.
