10 Insider Caulking Tips for the Perfect Seal

Caulking a window

Caulk is used to keep water and moisture where it belongs, preventing it from seeping into cracks and seams. A bead of calk around a tub prevents steam from invading the walls, and caulk around a window keeps the rain and weather out of your house.

Laying a bead of caulk is easy, but doing it without making a mess can be a challenge, and doing it so it seals properly and smoothly is essential. These insider tricks can help you get the job done right.

1. Use Masking Tape for a Neat and Even Application

Here is a trick to keeping that caulking bead looking straight and clean. Use masking tape around the seam you are caulking, keeping the two pieces of tape at a distance the size of the desired bead. Lay down your bead of caulk. Use your finger to tool the caulk by pushing the excess onto the tape. After tooling, remove the masking tape, and you'll find a nice-looking, straight, clean, smooth bead of tooled caulk.

2. Shine Your Shower with Car Polish

Next time you clean your bathroom, get out your car polish. Rub a coat of polish on your ceramic or fiberglass shower enclosure. You'll get a wonderful shine and the water will bead up and roll off before mildew or mold can begin to form. It will make your next cleaning time a lot easier. Plus, keeping your shower clean will help your caulk last and keep water out of your walls.

Warning: DO NOT apply car polish to the floor of the shower, or it will become a slippery place for an accident ready to happen.

3. Smooth Caulk with a Paint Stick

After you lay your bead of caulk, determine the width you want and mask it off with masking tape. Next, take a paint stir stick and clip off the corners to fit the desired width between the two pieces of masking tape. Smooth out the bead of caulk with the stick.

Tip: You can also use a clean popsicle stick.

4. Unplug a Used Tube of Caulk

Take the tube and cut off the nozzle end so that the hole is slightly larger than the first cut that is clogged. Next, drive a screw into the nozzle end of the hardened caulk and use the screw to pull the hardened caulk out of the nozzle. A screw with course threads, such as drywall or deck screws, will work the best.

The larger hole may produce a larger-than-desired bead of caulk, so be sure to employ other methods of protecting surrounding areas.

5. Repair Your Chipped Ceramic Tile

If your tile is chipped, the best caulk in the world can't keep the water out. The repair is simple enough that you don't need to worry. All you need is appliance touchup paint. This paint dries to a hard finish and adheres well to smooth surfaces. Appliance paint comes in only a few colors (white, almond, green, yellow, and black), but it can be tinted with other paint to match your tile.

6. Cap-off a Used Cartridge

So you just finished your caulking job, but there's product still left over in the tube. Instead of throwing it away, store your cartridge for later use. A plastic electrical connector is great for this and is an easy way to quickly seal and reopen the tube. If you can't find a connector, place a 2-inch nail into the end of the nozzle, then wrap the entire nozzle tightly in plastic wrap or aluminum foil. This will keep the caulk in the nozzle from hardening for use at a later date.

7. Avoid Adhesion Failure

Surface wood fibers can be appreciably damaged in as little as two to four weeks when exposed to direct, intense sunlight. This has been determined by the USDA's Forest Products Research Laboratory in Madison, Wisconsin (in repeated studies over many years). If caulk is applied to such damaged wood, it can lead to premature failure of the sealant. In reality, the sealant adheres quite well to the surface wood fibers themselves, but the surface fibers lose their attachment to the bulk of the wood, which is what will cause the caulk to fail. Make necessary repairs before you caulk.

8. Don't Use Oil-based Caulking around Windows

Make sure you never use an oil-based caulking compound around insulating glass (thermal-pane) windows. The vegetable oils in these types of caulking compounds aggressively attack polysulfide polymers, which are the primary sealants used for such windows. The polysulfide degrades, cracks, and causes the window to fail and fog up.

9. Expect Shrinkage

Sometimes "shrinkage" of a caulking bead is thought to potentially lead to performance problems with the sealant, but it depends on what type of sealant you're working with. While this can occur with some types of sealants (silicones and polyurethanes, for instance), for many other types of sealants it does not pose a real performance problem. Such products as Acrylic Latex, Butyl, SBR, Polysulfide, and others do not suffer severe performance problems when they experience a moderate amount of shrinkage during their cure.

10. Allow Elastomeric Latex Caulks to Cure

Always give elastomeric latex caulks plenty of time to cure before painting them; between one and three days depending on manufacturer instructions and the amount of caulk used. These types of caulk are much more elastic than any paint that is applied over them, and the paint can't stretch enough to avoid cracking during the caulk's curing (and subsequent shrinkage). Let the curing process fully finish; then apply paint as needed to the shrunken caulking.

>>Preparation for Sealing and Caulking