When Picking a Caulking Product, Here Are Some Things to Consider

Choosing the right caulk from a selection of tubes spread across a 10-foot wall display can be downright intimidating. A single tube of caulk can cost $1.50 to $14.

Regardless of what the caulk is labeled, its ingredients are the most important consideration in determining what it’s best suited for. What you want the caulk to adhere to and where you’ll want to use it determine the caulk you buy.

Caulking joints around doors and windows requires a sealant that is flexible and long-lasting, adheres to siding (wood, aluminum and vinyl), resists extreme weather conditions and, if it’s not painted over, withstands direct sunlight.

To seal flashing around a chimney, the caulk must adhere to masonry, roofing shingles and metal flashing and stand up to the elements unpainted. The warm, wet conditions of a bathroom require that a caulk resist mildew and moisture.

The tube label should provide the information you need to determine the caulk’s suitability for your project. If it’s to be unpainted, check if the caulk comes in a selection of colors so you can match adjacent colors of siding and trim paint. If you can’t find a match, use a clear caulk.

The label should also state whether the caulk is paintable or stainable, what kinds of paints and satins it’s compatible with and whether it requires priming before painting. The drying or curing time before painting should also be specified.

If you’re working in cool weather, check the recommended application temperature range. Some sealants can be applied at any temperature; others require a minimum of 40 degrees.

In some cases, reading the label will not give you a clear idea of how well the caulk will perform. To help choose the best caulk for the job, we’ve grouped them into categories, along with some of their basic characteristics.

* If cost isn’t a consideration, the new tri-polymer or copolymer caulks are the best choices for versatility (about $4 to $6).

Proflex by Geocel and Lexel by Sasho are multi-task sealants designed to adhere to dissimilar surfaces such as metals, glass and untreated and treated wood. With excellent adhesion properties and more elasticity than other caulks, these new-technology sealants can replace some specialty caulks such as butyl-rubber and asphalt caulk. But these formulas are flammable and should be applied with caution and proper ventilation.

* The high-end latex caulks such as 230 by DAP are also multipurpose. The most popular formulas are latex-base variations or combinations with silicones and acrylics. They’re easy to use, clean up with water and are almost as durable as the polymer formulas.

Just as expensive (about $4 to $6) are the 100% silicone caulks, the best choice when sealing damp areas. They shrink very little, remain flexible, are water-resistant and have bonding power for joining dissimilar surfaces.

They’re also the best for caulking around bathtubs, showers, sinks and other high-moisture areas. Some silicones don’t hold paint well, however, and they don’t bond to rot-resistant woods such as cedar, redwood and pressure-treated wood. As such, they’re not as versatile as the compound-latex and polymer formulas. Silicones can be applied in cold conditions.

* In the mid-price range are the acrylic latex-formula caulks (about $2 to $6). These represent the best all-around buys for many uses inside and outside the house, and they feature water cleanup. As silicones and other additives are introduced into the formula, the caulk becomes more durable.

In this category are adhesive caulks such as Polyseam-seal by Darworth and Phenoseal Vinyl Adhesive Caulk. In addition to sealing cracks, these caulks act as light-duty construction adhesives. Replacing a loose ceramic tile, setting ceramic soap dishes and installing vinyl baseboard molding are just a few of the jobs adhesive caulks can handle.

These inexpensive caulks (about $1 to $2) have been around for years and are suitable for indoor use only. Although oil-base caulks are inexpensive, they’re not always the best buys because they have a limited life and require mineral spirits for cleanup.

* Plain latex caulks, on the other hand, are easy to apply and clean up with water. They’re suitable for interior uses such as caulking woodwork when painting, but they’re not a good choice for areas exposed to weather.

This type of caulk is medium-priced (about $2 to $4) and is traditionally used to caulk masonry-to-wood or metal joints. It’s also good for caulking glass-to-metal joints and sealing aluminum and galvanized gutters. This type requires mineral spirits for cleanup and is more difficult to work with than the newer formulas.

Tri-polymer and copolymer caulks can be used for similar applications.

Both of these formulas are expensive, high-performance caulks (about $4.50 to $14) used primarily in marine applications. They have excellent adhesion properties and are waterproof. However, they are toxic until cured and precautions must be taken to provide proper ventilation and skin protection during application. Strong solvents are also required for cleanup.

* The best way to fill large cracks in difficult-to-reach areas is with foam caulk. But it’s sensitive to UV radiation, so it must be painted if it will be exposed to sunlight.

The foam sticks to just about anything and is messy to work with. It can cause skin and eye irritation, so wear eye protection and use the plastic gloves that come with the product.

* Rope caulk is an inexpensive, non-hardening, solid caulk used to temporarily fill cracks. It’s best suited to plug gaps between window sashes and doorjambs during the winter. Because it’s not designed to adhere, it can be easily removed when warm weather returns.

Rope caulk will last for a season outside, so it can be used to plug cracks between storm windows and other small gaps on the exterior of your house.