Grout Removal and Redo
DEAR TIM: The grout in my tub and shower area is a mess. It is difficult to keep clean and has actually crumbled in places. Is it possible to regrout over the existing grout? Or, do I have to remove the ceramic tile and start over? What type of grout should I use? Is it possible to achieve professional results, assuming that I have above average remodeling skills? B. E.
DEAR B. E.: Well, I have good news and bad news ... The good news is that you don't have to remove the existing ceramic tile! The bad news is that you can't regrout over the top of the existing grout. The old grout must be removed by hand or by using a small electric grinder.
There are two hand methods you can use to remove old grout. The remainder of the grout may crumble when you use a carbide tipped scraper tool specifically designed for grout removal. If not, you may have to use a fine tipped screwdriver and a hammer to remove the grout.
The carbide tipped scrapers can be found at most stores that sell ceramic tile. They are very inexpensive. Be careful, as they can easily scratch the glazed tile surface. You apply firm, but gentle pressure, as you draw the scraper across the grout. It may take repeated strokes before you remove a significant portion of the grout. Move on when you expose the unglazed edges of the tile.
Be sure to drape a cloth tarp in the bottom of the tub before starting this project. Loose pieces of grout can scratch the tub surface if you step or kneel on them. Remove the grout fragments on a regular basis to minimize scratch hazards.
If the carbide tipped tool does no good, you will have to chisel the old grout from between the tiles. This can be accomplished using a flat bladed screw driver or an old wooden chisel with a 1/4 inch blade. Tap the screwdriver or chisel lightly with a hammer. Once you have removed some grout, always chisel away from the grout which is still in place. If you chisel towards existing grout, there is a great chance that you will chip the sides of the tiles.
Once you have completed the job and regained your sanity, it is time to grout. I would suggest that you use a dry set grout with latex additives or a latex-Portland cement grout. These grouts mix with water. They offer superior bonding qualities. In addition, they tend to be less absorptive than standard Portland cement grouts.
Applying the grout is rather simple. You will need two important tools: a hard rubber grout float and a synthetic grout sponge with rounded edges. Two or three buckets of fresh water are also necessary.
Add water to the dry grout mixture, and stir until the grout resembles a creamy cake icing on a hot day. The grout should be firm, but not runny. Trowel the grout onto approximately 6 square feet of tile using the rubber float. Apply pressure to squeeze the grout into the grooves between the tiles. Remove excess grout by pulling the float across the tile at a 45 degree angle.
The sponge is used to remove grout from the face of the tile and to strike the grout joints. Squeeze as much water from the sponge as possible. Rub the sponge lightly in a circular manner across the grouted area. Rinse the sponge frequently. Once again, squeeze all of the water from the sponge. When the tile looks clean, turn the sponge on edge and glide it across the grout lines one at a time. Do this until the grout lines are smooth and uniform in appearance. Avoid using too much water. That is why your previous grout crumbled.