REPAIRS : Good Quality Caulking Compound Gets Job Done Right the First Time
The first rule of caulking: Don’t buy cheap caulking compound. Pay a little more for a good, durable caulk that will get the job done and save you money.
One particularly good choice for most exterior caulking jobs is a compound with a polyurethane base. It has excellent adhesion, strength and weather resistance and is widely used by builders in new construction. Properly applied, polyurethane caulk will maintain flexibility up to 50 years. You may not be able to find it at your local hardware store, but it is available from building and marine suppliers.
Another durable caulk with a 50-year life expectancy is the copolymer type. Usually labeled only as “new technology” caulk, it is widely available at home centers and hardware stores.
Other caulking compounds are better on particular surfaces or in certain situations. Butyl rubber caulking compound is the caulk to use in high moisture areas and below grade. It also works well on concrete block and brick and is excellent on aluminum siding. Silicone caulk is best for smooth non-porous surfaces such as glass, tile and metal.
Silicone is often added to ordinary acrylic latex caulk to extend its life to more than 25 years. Plain latex caulk is not long-lasting enough for use on the exterior of a house, but it is fine for interior jobs such as filling gaps around trim before painting.
Where should you caulk? Wherever two dissimilar building materials come together, most notably where the siding meets the foundation and where the siding touches the trim around doors and windows and at corners. You also need to caulk at the points where the siding comes in contact with decks, steps, pipes and chimneys.
The most common way to buy caulk is in tubes that fit into an inexpensive caulk gun. When buying caulk, keep in mind that a standard 10 1/2-ounce tube will produce an average-size bead 40 to 50 feet long--long enough to seal four windows or doors.
Caulk also comes in squeeze tubes for small jobs, and expanding foam caulk in aerosol cans is available for filling extra-large gaps. You can also buy caulk in rope-like strips that are good for temporary seals around storm windows or air conditioners.
To prepare for caulking, scrape away dirt, grease and old compound with a putty knife and finish with a wire brush. To ensure adhesion, clean the crack with a solvent such as mineral spirits. Fill cracks deeper than three-eighths inch with oakum or foam backer rod before caulking.
It’s simple to load a cartridge into a caulking gun. Just pull the plunger all the way back and slip in the tube of caulking. Push in the plunger and twist it to engage the ratchet. Then cut the tube tip at a 45-degree angle and push a long nail down the spout to puncture the inner seal.
To apply caulking, squeeze the gun trigger slowly and draw the top along the seam you want to fill. Work at a slow, easy pace, filling the joint completely. To be sure a joint is filled, many pros prefer to push the tube along the seam instead of pulling it.
It’s best to caulk on a mild, dry day when the outdoor temperature is above 50 degrees Fahrenheit. On a hot day, refrigerate the caulk for an hour or two to keep it from running.
If you are faced with cold-weather caulking chores, leave the caulk indoors, near a heating source, until ready for use.
For a neat job of caulking around interior surfaces, such as the edge of a tub, outline the caulking area with masking tape. Apply a bead of caulking and smooth it with the back of a plastic spoon. Wait for it to get tacky (about 10 to 20 minutes) before removing the tape.
To avoid leaking caulk when you pause, turn the gun’s plunger to disengage the ratchet and relieve the pressure.
Keep unfinished tubes of caulk fresh. You can buy handy screw-on caps, or plug the nozzle with a large common nail. Or use the plastic tip that you cut off the nozzle. Insert it pointed end first into the nozzle and cover with masking tape.
