During the useful life of any tile floor, tiles will loosen and have to be repaired. The level of difficulty of this type of repair is about a 3 on a scale of one to ten; one being the easiest and ten being the hardest. This type of repair is costly when contracted out. Certainly within the skill level of most homeowners and given the proper instruction, it can easily be done over a weekend. Let me give you a brief overview of how to fix a loose floor tile and save yourself an unnecessary labor charge from a general contractor.
First, you will need a few simple tools, which should include eye protection, gloves, broom, dust pan or shop vacuum, hammer, masonry chisel, small taping knife, bucket, grout that matches the original, grout sponge, and a high quality thin set. The thin set should be of a modified nature, meaning that latex based additives have been mixed into it during manufacture. These additives allow the thin set to cure quicker and have a more resilient bond with the floor. It’s good to have a spare tile or two just in case you accidentally crack the loose tile during the repair process.
The hardest part of the entire process is getting the loose tile off the floor. Even though the tile is not adhered to the sub floor any longer, it still will want to stay in place. The irregularities between the tile’s edges and the grout against them need to be removed. With your safety glasses in place, use the hammer and chisel and gently remove the grout around the loose tile. It is important to use gentle, downward blows with your hammer. You may not be Michelangelo carving David, but you still need to be delicate. Be deliberate and remove all the grout from all 4 sides of the loose tile. The grout should be completely removed until you expose the edges of the 4 adjoining floor tiles. Once the grout has been removed the tile should easily come up by hand. If this does not happen, gently pry the tile off the floor using the chisel. Make sure you protect the edges of the good tiles still on the floor.
Now that the tile has been removed from the floor, you will need to remove the thin set from both the tile and the floor. Using the hammer and chisel remove all the old thin set from the back of the tile. Be careful with hammering on the tile. Lay the tile on a firm surface such as a workbench, and take your time. One heavy handed blow from the hammer and your tile will crack. You do not have to be as careful with removing the thin set from the sub floor. Remove enough so that the face of the tile, when placed back in its original location, is below the plane of the floor surface by approximately 3/16 of an inch.
With the tile and floor free of any old thin set, it is now time to place the tile back in place. When mixing the new thin set, carefully follow the manufacturer’s specifications. The substance should have the same consistency of peanut butter when properly mixed. It should easily adhere to your fingertips and stick to them when you touch it. Using the taping knife, apply thin set to the back of the floor tile and the face of the sub floor. When properly done, the thin set should exactly make up the gap between the sub floor and the tile, allowing the face of the tile to lie in the same plane as the floor. Again, following the manufacturer’s specifications, allow the thin set to cure. From my experience, overnight will usually be enough.
The last step is to reapply grout around your newly placed tile. As always, follow the instructions recommended by the manufacturer. Using the taping knife, fill the space between the tiles with grout and wipe the excess away with the grout sponge. The sponge should be wet, but not too wet. Novice tile setters tend to use a sponge that has too much water in it. Too much water allows the sponge to remove an excessive amount pigment from the grout. The grout will then take on a whitish color that doesn’t match the existing grout color well. Wringing out the sponge as hard as you can you will be fine. An advanced technique is to feather the new grout over the old. This allows the colors to blend and won’t be as noticeable.
In conclusion, be diligent in cleaning the floor tile and sub floor of old thin set. Do your best to get the tile back in the same plane of the floor. Grout with care and feather the new grout over the old grout. If you follow these instructions to the best of you ability, you will have a completed repair equal to, if not better than, any contractor could have done for you.