Best Caulks and Sealants for Your Home Improvement Projects
Drafts, bugs and runoff water can enter your home in gaps as small as 1/64 inch, about the size of a straight pin. Caulk can be used anywhere to seal gaps or form a bond between different types of building materials. It can save money on energy bills by blocking drafts. Plus, it can keep out water and pests. This guide will answer questions like “what is caulk?” and help you decide what type of caulk or sealant to use for various projects inside and outside your home.
Caulk and sealants come in cartridges or squeeze tubes. There are several types of caulk and sealants you can use inside and outside your home: latex caulk, silicone sealant, polyurethane foam and specialty caulks like butyl-rubber caulk.
What is Caulk?
Generally, caulk describes any waterproof material that fills and seals joints between building materials. It is used for both new construction and repairs. Caulks are typically made from a flexible polymer such as latex or rubber because these materials are fully waterproof, can expand with temperature changes and absorb vibrations well. Unlike mortar or grout, caulk usually won’t crack and can connect materials on two different planes. For example, grout can only connect tiles sitting flat next to each other, while caulk can connect tiles at a right angle.
What is the Difference Between Caulk and Sealant?
The terms “caulk” and “sealant” are often used interchangeably, since both are used to fill joints and seams. The biggest difference between caulk and sealant is elasticity. Caulk is more rigid than sealants when dry. Sealants hold up better in spaces that are prone to a lot of expansion and contraction. For example, the best caulk for windows is usually a “sealant” instead of a true “caulk.” When choosing caulk vs. sealant for your project, decide based on how much stress there might be on the sealed area.
- Silicone is very flexible and acts as a water and moisture repellant, making silicone sealants the best caulk for windows and bathrooms.
- Use around the perimeter of windows to help seal the window to the header, sill, jack stud and jamb.
- Paintable silicone caulk can be used around the outside of window units to properly seal the window and the siding edge, or around the entire door unit.
- Use around sinks, tubs and showers.
- Use when installing bath fixtures to seal gaps between shower tiles, between sinks and counters, and around the base of the toilet.
- Use outdoors in areas exposed to direct sunlight or rain, as the silicone helps the seal last longer.
- In older homes: Seal where any siding overlaps the foundation to prevent air from entering. Fill and seal all exterior areas where different materials meet, such as around windows and doors.
- Cleanup for silicone caulk requires solvents instead of water.
- Sometimes known as acrylic latex caulk.
- Best for use with drywall, wood and masonry.
- Fill in gaps between crown moulding and baseboards.
- Seal a door frame in place and seal the subfloor at the bottom of a door frame.
- Use latex painter's caulk inside of doors and windows or to quickly fill cracks and holes in drywall.
- Use to install wood paneling without nails.
- Lasts 10 to 15 years but breaks down faster if exposed to water often.
- Cleans up with water.
Tip: Tub and tile caulk is a specialty performance latex caulk with added mildewcide to protect against mildew growth.
- A polyurethane spray foam insulation that expands to fill larger gaps and holes.
- Use around electrical outlets, exterior pipes and window jambs.
- The best exterior caulk for blocking large pest holes.
- Use a pest-resistant foam sealant for sealing exterior gaps and holes, since mice can eat through some types of sealants.
- Good for dampening sound.
- Can repair cracks in foundations of older homes.
- A specialty caulk for outdoor use only.
- Best for use with aluminum, metal, concrete, mortar, plastics, rubber, stone, vinyl and exterior wood.
- Good for gutters, siding and concrete.
- The best exterior caulk for roofing construction and repairs, since it can withstand extreme temperatures and creates a strong, insulating and water-tight seal.
- Cleanup can be difficult if you get this caulk on clothing, gloves, shoes or skin.
Caulks and sealants come in a variety of colors, as well as neutral white and clear. Find a color that matches the tile or other materials you are working with or find a white paintable caulk that you can color-match later. Select clear caulk or sealant for a subtle look that blends in wherever you use it.
Sanded caulk vs. unsanded caulk
Caulk can be either sanded or unsanded. Sanded caulk has particles in it that help it adhere to wet surfaces and expand in larger gaps without cracking. It has a grainy texture and appearance. Use sanded caulk any time you use sanded grout and in joints 1/8-inch or wider.
Unsanded caulk has a smooth appearance and texture. It’s most often used to caulk countertops and backsplash, since it creates a clean finish. Since sanded caulk can crack tile and other materials when it expands in too small of a space, unsanded caulk should be used to fill tight joints that are smaller than 1/8-inch wide. Unsanded caulk may not adhere as well as sanded caulk to wet surfaces and sanded grout.
Regular caulk vs. fast-drying caulk
Latex caulk and silicone sealant typically dry to the touch within 30-minutes, but they can take up to 24-hours to completely cure and be fully waterproof. Fast-drying formulas can cure in under 24-hours, depending on the temperature and humidity. Typically, the best advantage with fast-drying formulas is that they can be painted after an hour of drying time, speeding up the entire installation process. Regular caulk and sealants need to fully cure before being painted. Note that while latex caulk and silicone sealants dry and cure relatively quickly, polyurethane foam usually requires 10-days to cure.
Caulk tools and accessories
While you don’t need tools to use caulks and sealants, certain tools and accessories can make the job easier.
- Caulk gun: Using a caulk gun helps make sure you have an even application of caulk. It also prevents dripping and arm fatigue during big projects.
- Caulk strips: Similar to weatherstripping, caulk strips are pre-shaped rolls of sealant that have a peel-and-stick installation. Apply these strips in place of traditional caulk or over already-caulked joints for a finished appearance.
- Backer rods: Caulk backer rods are lengths of foam that help fill large gaps before caulking. Backer rods can add extra insulation around windows and doors and help limit the amount of caulk/sealant you need to use.
- Caulking spatula: This long, specialty spatula helps remove old caulk/sealant without scratching tile or other surfaces. It also helps smooth just-applied caulk/sealant for a clean finish.
The right caulk or sealant for your interior and exterior projects will create long-lasting, durable seals. Prevent leaks in kitchens and bathrooms and keep the weather and pests outside. Ready to find the caulks and sealants you need? The Home Depot delivers online orders when and where you need them.