Regrouting and recaulking ceramic tile above bathtubs and inside showers is relatively easy and inexpensive, requiring only basic household tools.
Here are some tips to make the job go smoothly:
Grout comes in a variety of forms, from small premixed tubes that handle patching jobs to dry powder grout for bigger projects. While the small premixed packages have the appeal of simplicity, they are not always the best choice. Often they're difficult to match perfectly with an existing grout color, even when that color is white.
Dry grouts are easy to mix in volume and can be used with an additive that retards drying. They can also be colored fairly precisely to match existing colors or to create new ones.
If you choose a dry mix, buy 1 to 3 pounds and make sure to get the drying-retarder additive as well. This is not the place to skimp on materials, and the additive will help assure a stronger grout.
Begin by pouring about 2 cups of grout into a small bucket. Follow by pouring a small amount of additive into the grout and mixing with a paint-stirring stick. You'll need to experiment, but the end product should have the consistency of toothpaste.
Use a rubber float to spread the grout over the tiles. Sweep the float in several directions to make sure the grout is forced deep into the joints. Finally, use the float as a squeegee to skim as much of the excess from the tile as possible.
Follow by wiping the remaining grout from the tile with a damp cloth, regularly rinsing the cloth with water until the surface is relatively clean. Finally, wrap the cloth over a finger and smooth the joints individually. With this much done, let the grout set for 15 minutes, or until the residue on the tiles turns a powdery white. Then buff the entire surface with a soft dry cloth until it's completely clean.
With the use of the drying-retarder additive in the grout, the drying time will be substantially extended, so a wet cure is not absolutely necessary. Even so, the longer the drying time, the stronger the cure. If you choose to wet cure the grout, tape a sheet of plastic to the walls so it hangs over the tiles in a way that allows you to easily reach inside. Then use a spray bottle filled with water to mist the tiles several times a day for a day or two to slow down the drying process and achieve a stronger grout.
When selecting caulk, you'll find two types to choose from: either silicone caulk or latex tub-and-tile caulk. While the latex variety is much easier to use, it has far less elasticity than silicone. And as caulk needs to absorb the natural flexing of the floor and walls without breaking, silicone is the better choice.
Here are some basic guidelines when using silicone caulk: Don't apply more than is absolutely needed to fill the joint, and don't apply more than you can smooth out before it gets tacky (usually no more than a 2- to 3-foot bead).
Cut the smallest opening in the applicator tip and run the tube tip along the seam in an even, angled path while applying uniform pressure to the gun handle.
To smooth the caulk, draw a finger lightly along the bead so that the caulk is arched against the opposing angles of the walls at roughly 45 degrees. A light touch is important here: Don't press so hard that some of the caulk is forced to the sides of your finger.