Cracked grout is something that many homeowners have to deal with at some point.
When your grout cracks it can be a very frustrating experience, and prompt you to make some repairs. Here are a few possible causes of cracked grout and what it means to you as a homeowner. Cracked grout can be caused by a number of different things. One of the most common reasons that grout cracks is because of settling in the foundation. When tile is installed on a concrete subfloor, there is always a chance that the foundation could settle a bit. The earth below your house could move and if it does, this can cause the grout to crack.
Grout is more flexible than the tile and therefore has a higher likelihood of cracking in this situation. Another common reason that grout cracks is because the floor below the tile is not structurally sound. For example, if you install tile directly onto a wood subfloor, this will not be strong enough to protect the tile and grout. Using concrete board is essential in this situation and it will help prevent grout cracking in the future. When you walk on tile that does not have concrete or concrete board below it, there is a good chance that the grout or tile will crack. One way to tell if the subfloor is the problem, you could knock on the floor where the grout is fine, then knock on the floor where the grout is cracked. If hear a different sound, that means the tile is loose.
Regrouting a loose tile is NOT a fix but just a band-aid over a problem.
The only fix is to rip up the tile, see why it came loose, address the sub-floor and install a new piece of tile. The chance of reusing the same tile you pulled out are slim to none. When repairing tiles, they rarely come out in 1 piece.