What Is the Best Kind of Caulk to Use in a Shower? 

Caulk is helpful for sealing and insulating showers. It’s effective in preventing water leaks and eliminating mold growth too. But with so many kinds of caulks out there, people wonder what the best type is for use in a shower.

The best kind of caulk to use in a shower is one that is waterproof and made from silicone, latex, or a combination of both. Silicone is best for nonporous surfaces like ceramic tile, glass, and metal, while latex is best for porous or uneven surfaces such as wood or stone tile.

There are many great kinds of shower caulk in the market. Read on to find out which ones are best for your specific needs.

What Type of Caulk Is Best for the Shower?

Caulk is mainly used for filling cracks or sealing joints in the shower. Though it’s important to caulk your shower to prevent moisture, dirt, and mold, your efforts will be in vain if you don’t use the right caulk made specifically for the job. That’s why the best kind of caulk for use in a shower has certain properties that keep it structurally intact in the bathroom, which has a unique environment of its own.

Silicone and latex are the two most popular kinds of caulking for showers. Some products already combine both. Let’s take a look at each of them in detail:

Silicone Caulk

Widely used for sealing nonporous surfaces, silicone is the most flexible type of caulk and has the greatest resistance to shrinking. It is recommended for sealing shower tiles in wet areas and other bathroom fixtures, or if your shower has two different types of materials that need sealing. A 100% silicone caulk formula is recommended if you have a fiberglass shower tub, a fiberglass enclosure, or a shower tub with caulked joints.

Pure silicone caulk is primarily used for waterproofing. It’s more expensive, though for many people, it’s worth the investment because of its lifespan (lasts over 40 years) and flexibility. Most 100% silicone caulks are already built to be mildew resistant, though the disadvantages are that you can’t paint over it and they tend to have a stronger odor during application.

Latex Caulk

Latex, also called acrylic or acrylic latex, is used for porous surfaces, and they come in interior and exterior grade. Interior grade latex caulk cannot be used outside, while exterior grade latex can be used both inside and outside your home. Keep in mind that exterior grade latex should never be used in the shower; always choose an interior caulk as they are made for this specific purpose.

Latex caulks last longer,  can be painted over, and have better mold and mildew resistance though they tend to dry harder compared to silicone. Additionally, latex caulk is more affordable, dries faster, and more versatile. It is best suited for filling in small gaps. Latex caulk has a minimal odor, though it tends to weaken once exposed to sunlight or extreme temperatures.

Polyvinyl acetate (PVA) is similar to acrylic latex, except for the fact that it’s formulated with polyvinyl and not latex. This is another option as it’s durable, mildew- resistant, heat resistant, and easy to apply. It can also be painted over, though it’s not as water resistant as silicone.

Silicone and latex combination 

Many people prefer to use a combination of both silicone and latex, as it offers the best of both worlds. It’s more moisture-resistant than a standard latex caulk, but also durable and flexible because of the presence of silicone. It is best used for shower areas that need moderate waterproofing.

Factors to Consider When Choosing a Shower Caulk

Mold and Mildew Resistance

Most pure silicone or siliconized latex / siliconized acrylic caulk are already formulated with fungicides and mildewcides, which are chemicals that prevent the growth of fungus and mildew. Mold and mildew resistant caulk can usually be identified easily if the manufacturer indicates that it’s ‘mold-proof’, ‘mildew-proof’, or made ‘for bath use’.

Packaging

Caulk comes in a variety of packages and sizes, each of them appropriate for various DIY scenarios. For example, if you are going to caulk just one shower and perhaps seal around shower doors, the small hand-squeezed tubes that are 5.5 oz. are ideal. This size allows for easy application while giving you full control of the flow. On the other hand, if you are going to seal around the shower tub perimeter, go for caulk cartridges.

However, a 10.1 oz. size is  meant to be applied with the use of a caulking gun and can be ideal if you have a larger project at hand. Caulking guns can be more difficult to use for those with no previous experience applying shower caulk.

Color

Silicone, latex, and siliconized latex caulks are available in a wide variety of colors. Clear caulks, the most versatile kind, apply white then usually dry to a transparent or clear color. Clear caulk is recommended if you want to make sure there is no color contrast in the shower while white caulk looks good with most shower color schemes.

Dry and Cure Time

Caulk packages list dry time and cure time. Dry time tells you how long it will take for caulk to be dry to the touch, while cure time tells you when the caulk has fully set and will be ready for exposure to water. Pure silicone and silicone/latex combination caulks usually have the same dry and cure times, which can range from one up to 12 hours for drying, and 2 hours up to 10 days for curing. If you are caulking the one shower you have at home, always go for products that have faster drying and curing time.  

Frequently Asked Questions

Which parts of the shower should I caulk?

Showers can benefit from caulking in numerous places, especially the pans, walls, shower doors, joints, and handles. The shower pan, or the area where the pan meets the wall, should also be caulked. Check if there are large gaps that need to be filled, which can happen if the tile job wasn’t done very well, or the tiles were not cut evenly.

Can silicone caulk be applied over latex, or vice versa?

If your old caulk has cracked and no longer seals well, don’t be tempted to apply new caulk over it without removing old caulking. Doing so will not result in a strong bond, resulting in even more leaks or cracks on the new caulk.

You can apply a new caulk after you have removed the old caulk. Use a good quality caulk remover to help soften the silicone or latex caulk. Then use a utility knife or scraping tool with a clean, fresh blade to slice up the softened caulk. Clean the remaining area thoroughly with rubbing alcohol to remove any residue. However, if you find that the caulk is extremely thick, you might need to use needle-nose pliers to pull the old caulk. A sharp putty knife or painter’s 5-in-1 tool can help you get rid of the remaining caulk chunks.

The final step in removing old caulk to prepare for a fresh application is to remove mildew with a solution of 1/3 cup bleach to 1 gallon of water, or a concentrated mildew killer. Use a foam brush to apply it on the area exposed by the removed caulk; scrub using a brush, rinse, then dry with a clean cloth.

What shower caulk do we recommend?