Regrouting old tile can add new life to an otherwise tired and worn bathroom, kitchen or entryway.
Step 1: Clean the tile with a good nonresidual cleaner such as TSP or Dirtex. If you are grouting a bathtub or shower, be sure the soap scum is completely removed before proceeding.
Step 2: Use a carbide-tip grout remover or grout saw to remove at least two-thirds of the old grout from the existing joints. If you can’t find a carbide tip tool, a good carton knife with extra blades will suffice. Be careful not to chip or scratch the tile as you work the grout out of the joints.
Step 3: Vacuum up the old grout and use a barely damp sponge to wipe away excess debris. It is very important that the grout joints are clean and completely dry before proceeding. When grouting a tub or shower, shut off the water supply to avoid any accidental water disasters.
Step 4: Pour a small amount of cold water into a clean bucket and slowly add powered grout until the mixture reaches a soft butter like consistency. Only mix as much grout as you can use in 30 minutes.
Step 5: Continue stirring the grout for five minutes and then let it set for 10 to 15 minutes. This allows the moisture and additives to properly bond with the grout material. Stir the grout again after it has “slaked” and continue to stir it occasionally though out the grouting process.
Step 6: Scoop a handful of grout onto the surface to be grouted. Use a good quality rubber float to spread and press the grout into the joints. Hold the float at a 30 degree angle as you spread the grout. Use the float edge to firmly pack grout into all the crevices.
Step 7: Once the joints are packed full, use the rubber float to remove as much excess grout from the tile surface as possible.
Step 8: Let the grout cure for 15 to 20 minutes and then carefully clean off the tile surfaces with a lightly dampened sponge. It is very important that you do not allow any water to seep into the newly grouted joints. Water will compromise the integrity of the grout and cause the joints to fail.
Step 9: Wait two more hours and then use a lint free cloth to remove the white haze on the tile surfaces. Be careful not to disturb the grout joints.
Give the grout at least a full 24 hours to cure before using the surface area. Keep the joints completely dry for three days and then seal the grout with a penetrating grout sealer to complete the process.