Caulking is used to prevent water damage outdoors at window trim, door trim and siding connections, and at locations where water leaks might occur. It is also used inside to water-seal sinks, tubs and showers. Other applications inside the home include hiding gaps in woodwork connections and repairing long narrow cracks in walls and ceilings. Here is the secret that will help you to determine whether to make a repair with caulking or putty. Although they often can be used interchangeably, caulking is specifically designed to fill long narrow joints; putty to patch small holes such as those made by nails.
Caulking to prevent water damage is a necessary evil that is, at best, a stopgap measure. Temporary or not, it is important to get the longest life out of each caulking application. To accomplish this, it is important to match the appropriate type of caulking to the job at hand. The following are a few examples of how to get the most for your money when caulking.
Latex caulking is the easiest type to use. It can be cleaned with fresh water, and a little soap helps. A smooth application is guaranteed by wiping the bead into place with a wet sponge or lint-free rag. An alternative is an index finger, despite the threat of a splinter. Latex caulk can be used indoors on woodwork connections, where woodwork meets wallboard and on the wallboard. Gaps being caulked should not exceed one-eighth to three-sixteenths of an inch in width and should be free of loose debris. Keep in mind that of the hundreds of types and brands of caulking, there are only one or two that work in wet conditions - reason enough to make sure that the area to be caulked is completely void of moisture. Because it's water-based, latex caulk has the tendency to shrink as the water evaporates. It is not particularily flexible. If it is used to seal a joint that moves or vibrates, the joint soon will reopen.
Pure silicone caulk will last longer than latex, won't shrink and is flexible. Unfortunately, it never dries completely and therefore it is not a good idea to use it in areas where it comes into contact with folks in nice clothing. One brush-up against a bead of silicone, even after a year, and you can kiss that item of clothing good-bye.
A caulking that is as user-friendly as latex, and almost as pliable as silicone, is an elastomeric caulk fortified with silicone. The compound is easy to apply and dries to a paintable condition. If silicone is the caulking of choice, be sure to purchase the paintable kind even if you don't intend to paint it. Here's why: The surface of paintable silicone dries to a point where it can be touched without sticking to your finger. Under optimum conditions, an elastomeric caulk fortified with silicone will outlast the person making the application.
Another long-lasting caulk is Acrylic fortified with silicone. Acrylic is a more durable base than latex, but not quite as flexible or long-lasting as a siliconized elastomeric. Caulking is in many ways similar to paint. It should be applied only to a very clean, completely dry surface. Drying (curing) time is a factor that has a great deal to do with lasting quality. Thus, caulking should be done during the spring or fall when temperatures are moderate.
Specialty caulks abound for use with projects like tub and shower maintenance, concrete repair (that's a big one) and even repair of cracks in tile grout. However, it is important to note that most caulking is not intended to be used to fill gaps that are wider than three-sixteenths to one-quarter inch in width. The shrinkage associated with most water-based caulking compounds makes filling wide gaps impractical and not cost effective. In such instances latex-based patching compounds are more appropriate.
Polyurethane caulk is at the top end of the list for lasting quality, but is not easy to use. The person applying this caulk often is heard uttering something like, "Now what am I going to do, I have caulking stuck to everything?" Unlike most other caulking products, polyurethane cannot be cleaned up with water.
If you will be caulking the entire exterior of your home, you might use as many as 12 quarts or more of caulking. Latex is about one third the price of the better products we've mentioned, but it will probably not last one twentieth as long. And considering the time that it takes to caulk the exterior of a home, we suggest going with the high-end products where you'll get the best bang for your buck.