The majority of tile removal and re-installation will occur around the bathtub or within a shower enclosure. The reason that the deterioration of tile occurs in these areas, is an inadequate maintenance of caulk joints, or simply the incorrect installation of the tile, and or sheathing under the tiles.
Once again, as we have repeated within this webpage, the entire functionality and integrity of the surface tile application depends upon the proper stability of the sub-base material. If the installation of the sub-base is inadequate or incorrect, the tile installation will be compromised.
Dependent upon the extent of the tile deterioration, will determine the need to either re-grout the installation, or simply remove the entire field of tile, as well as, in many cases, the sheathing that has been installed over the structural members of the home. Once a tile installation fails, unless replaced immediately, water, mold and additional deterioration of sub-surfaces normally occurs. All of the compromised materials must be replaced.
If only a simple re-grouting is required, one of the easiest tools that I have found to remove the grout between the tiles is a common bottle opener. The V shaped point of the bottle opener, will easily scrape the existing grout out of the joints, and allow the re-installation of new grout. New grout can either be mixed dry, with water, or can be purchased already mixed. This is your choice, the premixed grout according to the promoting manufacturers have additional waterproofing additives or bonding agents included in the grout. I have always found that mixing the powdered grout has normally resulted in a good job, however, if you prefer the premixed, there is nothing wrong with the material. The grout is re-applied into the joints with a rubber trowel, which can be purchased at any hardware store. The rubber trowel will allow the application into the tile joints over the entire surface, without fear of scratching or marring the tile. In addition, with firm pressure, the grout will be forced into the joints and provide a consistent and tight installation.
If the existing tile is too compromised to simply remove the old grout and re-grout the joints, then I suggest the total removal of the entire tile field, to ensure that the job is properly performed.
If the existing tile is removed, the bathtub or shower base should be protected. I have used an old blanket of towels to cover the bottom of the tub and the shower base. Remember that the removal of hard tile will entail the dropping of these hard tiles down onto the base of the shower or the bathtub. Therefore the protection of surfaces, that will remain, is important.