Like any other room in your house, your bathroom will periodically need maintenance to keep you from having to pay for costly repairs later. One of the areas that's most often ignored is the caulk in your bathtub. Caulk keeps water from entering joints and seams between tiles or other areas of the bath. If the caulk becomes dry and cracked, or otherwise damaged, you could have to replace large areas of tile. Entire rows can become loose because of water seepage, and frequently, mold growth occurs.
Caulk works because it is both flexible and functions as a glue. This allows it to keep tiles in place and water out, despite changes in surrounding area due to moisture and temperature variances. Caulk which needs to be replaced can be brittle, dry and cracked, or soft, mushy and moldy. Either way, you must get the old caulk off of the tub before you can properly apply new material. Otherwise, your new caulking job won't seal properly, and all your effort will be wasted.
Pre-clean the area you'll be working in with your usual bathroom cleaner. Then figure out what kind of caulk has been applied previously. A soft, rubbery caulk is probably silicone, whereas harder materials are probably acrylic or latex. What kind of caulk is already on you tub won't affect what you put down when you replace it, but it can make a difference in the way you remove it. Silicone can be removed with a sharp knife, often in one strip. Latex or acrylic/PVA caulk may need to be scraped with a screwdriver, softened with a heat gun, or removed using a caulk softening product. Wipe down the area as well as you can once you've removed the old material. You may wish to use a mildew killing product as well.
After the area is prepared, you must choose which caulk to apply. Silicone is the most flexible when cured, but may be less mildew resistant than latex or acrylic caulks. Hybrid siliconized caulks are available, which are intended to give the best features of both types. Whichever caulk you choose, be sure it's designed for use in the bathroom.
For a small job, you won't need a caulk gun. Squeeze tubes are available that will work just fine for the amateur. Cut a small hole at the end of the tube to control caulk flow, and work with care. Blobs and squiggles in your caulking job are noticeable and hard to repair. Roll caulk is also available, but it can be hard to apply in a straight line. Keep a damp sponge and a roll of paper towels around for cleaning up spills and blobs. Work in small areas, and smooth the caulk with a damp finger as you finish each area.
It's important to make sure that you've budgeted enough time to do the entire job at once. Caulk works best when applied in a single attempt, rather than in stages. Also, be sure that no one will be using the tub while the caulk cures. You should let it sit overnight to be sure that the tub is properly sealed. Maintaining your bathtub will save you lots of pain and money in the future.
