If you have been shopping for caulks lately, you have probably discovered that it is no easy task. The number of products available in the market is enough to leave you thoroughly confused.
”In part, this is because many of these compounds are highly specialized,” says John Renaud of Sager Sealant Corp., a Chicago caulking and waterproofing company. ”But variety exists because the industry progressively made better products and never stopped making the old ones.”
Caulking compounds are materials used to fill and cover cracks, holes and joints, inside and outside our homes. They can be used in bathrooms, kitchens and attics to prevent moisture infiltration, and around doors, windows, chimneys and other exterior joints to prevent hot or cold air loss.
The type of caulk you use will depend on the particular application you have in mind, Renaud says. But he adds that the chemical base of the product determines the quality of the job.
Even though there are hundreds of caulks, most can fit into a few categories: oil-based, butyl rubber, latex, acrylic latex, silicone, polyurethane and solvent-based acrylic.
”The more sophisticated sealants are, of course, more expensive,”
Renaud says. ”But why bother doing a job that will not last because the product is of poor quality?” These products are generally not available at hardware stores, but many distributors sell them at the retail level. Tremco, Nameco and Sonneborn are among the product lines that Renaud recommends.
Following are his recommendations as to the most suitable types of caulking compounds for each job:
INTERIOR USES
Most people first encounter caulking compounds when their bathtub needs recaulking. Despite the number of products available, this is the easiest choice to make.
”All bathtub caulks are basically alike,” Renaud says. ”They are made of a sanitary silicone caulk, which is mildew resistant. The difference between one brand and the other is like the difference between Coke and Pepsi.”
So, as long as the tube says ”bathtub caulk” or ”tub and tile caulk,” you are safe. Dow Corning and General Electric are two of the major manufacturers of silicone caulk. Unfortunately, the sanitized variety is available only in white.
Bathtub caulk can also be used for joints between kitchen countertops and walls, tubs and floors, tubs and tiles and toilets and floors. It dries very fast, so it must be forced into the joint immediately after application. Under normal conditions, bathtub caulk should last 5 to 10 years. If it fails sooner, it is usually because the tiles shift when moisture gets behind them; there are structural shifts in the building; or children pick at the caulk and remove it (silicone is a soft rubber and it doesn`t bond very well). Renaud points out that, because this caulk contains a poison that kills fungus, children should not be allowed to touch it.
EXTERIOR USES
Around window frames and doors: If your house has aluminum siding, stay away from butyl caulk, Renaud warns. It doesn`t seal well and it shrinks too much. When applying caulk between aluminum siding and window frames and doors, use a polyurethane or solvent-based acrylic caulk, such as Vulkem
(manufactured by Nameco) or Mono (manufactured by Tremco).
”Although more expensive, polyurethane is designed to take the movement of the joints and could last up to 25 years without requiring maintenance,”
Renaud says. So the long-term results are well worth the initial outlay.
If your house has wooden siding, use a solvent-based acrylic caulk. ”In fact, use this type of caulk whenever wood is involved,” Renaud says.
If you have masonry walls and aluminum windows, use a polyurethane caulk. With masonry walls and wooden windows, use a solvent-based acrylic caulk, such as Mono.
For patios, driveways and chimneys, use a polyurethane caulk such as Vulkem to fill concrete cracks or for joints between masonry and concrete.
Once you have picked the appropriate type of caulk for the job, you will want to follow these guidelines.
1. Most caulks come in disposable cartridges that end in a tapered, plastic nozzle. You must cut this nozzle at a 45-degree angle and follow label directions as to the desired flow thickness (small, medium, large).
2. You will need a caulking gun, available at hardware stores, to apply caulks from a cartridge.
3. The surface should be thoroughly clean. If you are recaulking, use a wire brush to remove all remnants of the old caulk. If necessary, use a solvent such as Mek (manufactured by Sunnyside Corp., Wheeling) to dissolve pieces that are hard to remove. ”The cleaner the joint, the longer the new sealant will last,” Renaud says. If you have several very small joints to caulk, you may save time by using a polyethylene tape (also known as a bond breaker tape) to form a new surface on which you can apply new caulk.
4. The surface should be completely dry.
5. Priming should not be required in most cases. ”If a manufacturer says his product needs priming, he`s saying his sealant doesn`t bond well,” Renaud says.
6. Never apply caulking when the temperature is lower than 35 degrees.
7. Apply caulk with the gun and use a moistened small spoon or your finger dipped in water to force it into the joint. Hold the gun at a 45-degree angle and gently push the bead along the seam.
8. Read manufacturers` labels to allow for proper curing and drying time. 9. Some caulking compounds should be applied in well-ventilated areas and you may need to wear a respirator. Again, read the labels carefully.
Following are some distributors who sell the recommended caulking compounds at the retail level:
— Glenrock Co., 140 W. Lake St., Northlake. Chicago telephone: 378-0800. — Ink-Smith Inc., 3280 N. Milwaukee Ave. 777-5825.
— SCS, Sealant & Coating Systems, 240 James, Bensenville. 860-7878.
CAULK
— Oil-based caulk: Cheapest among all caulks. It has the poorest performance record. It dries hard, it doesn`t seal well and can deform permanently. If the surface is porous it will require priming.
— Butyl rubber caulk: Butyl provides better adhesion than oil-based caulks and it offers adequate water resistance. But its quality is relatively poor. It tends to shrink too much and it peels.
— Latex caulk: This caulk works well on small joints and nonmoving parts. Clean with water. However, latex dries hard and may become brittle. It is intended only for interior use and is not recommended for use in permanently damp environments.
— Acrylic latex caulk: The widest selection of colors is available in this type of caulk. It dries fast and cleans up with water. Recommended only for interior use in a dry environment.
— Silicone caulk: Very elastic, flexible type of caulk. Ideal for large, moving joints. Although it generally does not bond very well, it provides adequate adhesion to glass, metal and ceramic surfaces. Most silicones cannot be painted.
— Siliconized acrylic latex caulk: For interior and exterior use. Very elastic, quite flexible. Adheres well to wood, metals, glass, tile. Does not stain, crack or shrink. Dries fast.
— Polyurethane caulk: Available in many colors. Excellent for use in large, moving joints. Ideal for concrete and masonry. Elastic, withstands a great deal of flexing without permanent deformation.
— Solvent-based acrylics: Excellent bonding properties and good color stability. Ideal for exterior wood surfaces.
