Worn out grout looks crumbly and may be permanently stained.
You really need to use a grout saw to remove the old grout and then clean the grout lines with a sponge. A grout saw comes in several different sizes the one we used was purchased at a hardware store for about four dollars.
Since the grout is damp after you wipe away the excess grout you will need to let it set for about an hour before you fill the joints with new grout. You can purchase pre-mixed grout, which is extremely convenient you donít have to worry about the mess of mixing new grout and what to do with the left over grout. You can use your finger to force the grout into the joint and be sure new grout is level with the existing grout and the joint is smooth with not gaps.
After about another hour gently wipe away the excess. Then let it stand for about two days before getting the new grout wet. In other words you will need to use another bathroom if you are repairing grout in the shower.
Remember your bathroom doesnít have to look like a cheap motel bathroom especially when you can make it look like a five star resort!
Here is some more information we found for you about taking care of your grout and your tile!
If you are cleaning old grout you will want to scrub it with wax stripper of a heavy duty cleaning solution. Then you will need a grout brush to get it was clean as possible.
You may need to use a bleach cleanser on stubborn stains be sure to rinse well. Again, you canít put in new grout until the area is good and dry. Instead of using pre mixed grout you can apply a coat of masonry sealant to keep it from absorbing stains and dirt in the future. If you are fighting mildew stains, it will be a long fought battle until you discover the source of moisture, which is causing the mildew. To get rid of the mildew at least temporarily, scrub the area with a 1 and five parts solution of liquid chlorine bleach and water. Then be sure to rinse thoroughly. This will get rid of the mildew for a while, but donít be surprised if it returns.
If your grout is colored and you are fighting dirty stains, you might want to try a grout brush and a heavy-duty cleaner that contains no bleach. When the grout is nice and clean (and dry-donít forget!), apply a coat of masonry sealer to keep it from absorbing so stains and dirt in the future. If the colored grout is very stained, you may want to try a mixture of 1:5 liquid chlorine bleach and water then rinse. However, the bleach may remove the color along with the stain.
The great thing about ceramic tile floors is that they don't need any wax or floor finish, and all you have to do is sweep and mop them regularly to keep them clean and shiny. Mop with clear water (or add just a dab of liquid dish detergent), and change the water as soon as it gets cloudy. Too much soap or dirty water will leave a dulling or sticky film. Don't use brown or black nylon-backed scrub pads on ceramic tile, or you could scratch the surface.
Re-grouting and Sealing Tiles
If you have ever tried to drill or hammer through tile, you know from personal experience that tiles have hard, sealed surfaces. Yet grout is porous and absorbs water, so it can get moldy. It can even let water pass through into the wall. Once it is in the walls the potential for water damage and continued problems with mildew is great. As we mentioned earlier, mildew will become an on going problem if the source of the moisture isnít found and dealt with properly.
You should consider sealing your tile and grout periodically to moisture penetration, especially in the bathroom and other tiled areas that are exposed to water. If you are beset by mildew problems it is probably best to replace the grout completely. First clean the grout joints in the ways we mentioned above, then apply a 100% silicone or water-based grout sealer to the joints. If the tile is glazed donít worry about getting some sealer on the tile surface, just be sure to wipe it off before it dries.
If water has indeed seeped into your drywall you will definitely need to replace the drywall.
If there are cracks in dry areas it is more than likely a sign of settling of the underlayment or shifting with changes in temperature.
If the cracks are small and clean, you can just press in new grout with your fingers. If cracks are large and have dirt or mildew in them, first scrap out the old grout with a grout saw as we mentioned above. Then vacuum or brush out any dust or dirt from the joints. Be sure to use a cleaner to remove any dirt, oil or soap scum and of course, give it time to dry. You can buy a mildew-resistant grout with a latex additive to grout the joints and apply it to the area you are repairing. Then clean the tiles off with a sponge and let them dry.
If you donít use a pre-mixed grout you will have to mix your grout at home.
There are two different types of grout: sanded and non-sanded. Sand is used to make sanded grout strong. You will want to use it for joints wider than 1/16 inch, such as larger tile on floors. Usually you will find non-sanded grout is mixed with a latex additive to make it stronger and more workable. Non sanded grout is used for joints less than 1/16 inch wide, like for smaller wall cracks and countertop tiles.
The color of grout you choose will greatly effect the look of your tile. Using a white or a light colored grout highlights the color in tile. Use light grout on a light tile and you will find the grout is good for hiding any mistakes you've made in setting the tile. However, donít use a light-colored grout on floors where there is a lot of outdoor traffic because it will get dirty quickly and lose its luster. Gray is a good neutral color and it wears well on floors. If you want to emphasize the geometric pattern of your layout, choose a dark grout with a light tile, or light grout with a dark tile.