Best Caulk for Showers, Tubs, and Bathrooms in 2025

Caulk for Showers, Tubs, and Bathrooms Buying Guide

It is quite a daunting task to find the perfect caulk for your bathroom. With a variety of adhesives and applications, no two caulks are alike. The following tips will help you make an informed decision before rushing out to the local store.

Factors:

• Mold & Mildew Resistance
• Durability
• Gap Size
• Cure Time
• Paintable
• Joint Movement Capability
• Cleanup
• Cartridge vs. Squeeze TubeType of Caulk

Type of Caulk

The type of caulk you choose for your bathroom is important because the wrong type can lead to mold, mildew, and rot.

Those are three things that no homeowner wants to deal with!

Let me tell you a secret. Actually, it's not a secret. But it's not something not many homeowners know unless they are experienced in caulking.

The secret is that you should use a 100% silicone caulk in your bathroom for areas that get wet or are prone to moisture because silicone is naturally waterproof. If it is pure silicone, water cannot penetrate the bead of caulk if applied correctly.

In bathrooms, silicone has excellent adhesion to nonporous surfaces such as showers, baths, and sinks. You can also use it around your kitchen sink.

Silicone is also naturally resistant to the growth of mold and mildew.

What about your bathroom's baseboards and other areas that get moist from humidity, but not wet? In those instances, we don't recommend silicone. Instead, we recommend a paintable and sanded caulk for a professional look.

In humid areas, use an acrylic caulk rated for bathrooms, but not on surfaces that get wet. Even if the caulk has silicone added, since it's not 100% silicone, it's still not the best choice for wet areas.

You should note that these recommendations are different from other recommendations around your house.

Outside your house, a pure silicone sealant isn't recommended since it has poor adhesion to porous surfaces. For exterior surfaces such as brick, masonry, or wood, we recommend non-silicone formulated caulk. A great choice would be a specialty brand such as OSI Quad.

In areas that are away from water, the best caulk to use inside your house is a traditional caulk such as acrylic latex with added silicone. The material is easy to clean with water, and it holds up well to seasonal changes in humidity when moderate expansion and contraction occur.

Moisture Resistance

Caulk for your bathroom should also be waterproof or have a high moisture resistance.

In general, silicone is recommended for use in wet areas of your bathroom. It has natural waterproof abilities and is resistant to cracking, yellowing, and shrinking.

But don't make the mistake some people make and assume that you can apply it to wet surfaces since it's waterproof.

Silicone only adheres to a dry surfaces, so make certain the surface is completely dry before application.

Mold Growth & Mildew Growth Resistance

When choosing a caulk, you should also consider how well it resists mold and mildew growth. 

Mold spores are everywhere. They may be hard to see, but don't let that fool you: they are everywhere. However, mold does not like to live in places that are dry and exposed to light.

It will grow on anything organic and wet, like wood or food, as long as it is kept dark, like in a dark closet or behind furniture. However, it cannot grow on silicone sealant. Because silicone is waterproof, it is used in bathrooms for baths and sinks. But if the silicone gets gunked up with mold yummies (ex., skin cells, fecal matter, dirt, etc) then mold begins to grow.

When there are gaps or holes in the caulk, it can also grow on organic material behind it.

Some types of shower caulk now come with mold prevention additives, and they come with longer mold and mildew warranties than other types.

We recommend sticking with a silicone sealant, making sure there are no holes or gaps, and keeping your caulk bead clean. Clean it gently with a toothbrush and water every couple of weeks. 

Durability

The durability rating of caulk is similar to a warranty. Caulk is typically warranted for a specific period of time by the manufacturer. When it fails, what happens? Usually they will refund the money if you show them the receipt.

There's just one problem. Will you still live in the same house in 50 years, have the same caulk in your bathroom, have your receipt, and be willing to undergo all of that trouble for a few dollars' refund? Probably not. The majority of homeowners do not save receipts for caulk purchases.

Why are durability ratings important? It's simple. It provides an indication of the caulk's longevity. Generally, caulk with a higher durability will last longer.

Gap Size

A bathroom caulk's gap size rating indicates how large a gap it can fill.

Imagine that you have an inch-wide gap between your tub and its surround. Most shower caulk cannot fill this gap. Fortunately, you have two choices.

In the event you can't find caulk that will fill the gap, you might be able to trim it out with some wood or trim.

You might also try using a backer rod on the gap.

If you want to ensure your caulking will create a watertight seal, you should follow the instructions provided by the manufacturer and apply backing material to recesses too large to be sealed with caulk alone. In bathrooms and around a shower stall especially, this is true.

It can be tempting to use excess caulk in wide or deep gaps, but this is unlikely to be effective. Use backing material to keep the joint narrow and clean to ensure that the caulk creates a tight seal.

Cure Time

Caulk needs time to cure before using your bathroom.

Let's say you're using shower caulk to seal a gaps and prevent water from leaking out of your shower pan.

Using the shower before the caulk has a chance to create a waterproof seal may cause holes and gaps in the caulk bead, reducing its durability and allowing water into your walls.

So make sure to let the caulk cure before using your bath or shower.

Paintable Caulk

There are two types of caulking that you can use in a bathroom. Silicone is a very strong type of caulk, but it cannot be painted. If your walls are painted, you might consider using silicone tinted to match them. However, for baseboards, you're better off using a paintable colored caulk since it can be painted in any color you like.

Joint Movement Capability

A lot of people fill large gaps with a caulk that isn't flexible, then expect it to never crack. In fact, caulk cracks all the time and it totally sucks!

Why does caulk crack? When the seasons change, your house's humidity changes (as well as after taking a hot bath or shower with warm water) and these changes in humidity cause materials to swell or shrink.

Using a flexible caulk is the best way to prevent cracks. How do you know if the caulk you are going to use is flexible? It is usually printed directly on the tube. Caulk containing silicone, an advanced polymer, or an elastomeric sealant is likely to be flexible and crack-resistant.

Cleanup

Cleaning up excess caulk is never fun. Silicone caulk is difficult to clean and usually requires mineral spirits. If the area you caulked is smooth, you might be able to remove the excess using a utility knife (just be careful). There are some caulks (usually acrylic latex) that can be cleaned up much easier than silicone, as they only require some water and a paper towel. 

It is possible to avoid a lot of cleanup by doing a good job of caulking, especially if you use the soapy finger trick. Simply smear some dish soap on your finger and smooth out the caulk bead for a clean finish. Since most caulk doesn't adhere to soap, it will not cling to your finger, resulting in a smooth, mess-free bead during application.

A plastic putty knife can be used to get a smooth caulk bead when the soapy finger doesn't work. Practice makes perfect, but if you don't want soap on your finger, this is a good solution.

Whatever method you choose, keep in mind to apply the correct amount for the right bead size. Do not apply too much or too little.

Another trick is to use a dripless caulk gun which automatically relieves the pressure on the caulk tube by moving the plunger back slightly after releasing the trigger. It might sound insignificant, but it can avoid a huge mess!

Cartridge vs. Squeeze Tube

Lastly, decide whether you want a 10 ounce tube of caulk or a 2.8 ounce squeeze tube before you buy.

If you need to caulk many places, the larger cartridge tubes make sense. They are less expensive and easier to use. You'll need a caulking gun to get started. A manual plunger-style caulking gun can be purchased for $10 to $50 if you don't already have one. The next step up is a cordless caulking gun, which costs between $75 and $250. If you already own a compatible battery, you can save money by purchasing just the tool.

What about caulk squeeze tubes? When should you use them? If you have a small amount of caulk to apply, a squeeze tube is perfect for touch-ups. You can also use it when you need to reach an area that's hard to reach with your caulk gun. In this case, a squeeze tube is ideal.

Apart from the high price per ounce, squeeze tubes' main disadvantage is the limited color selection. Although white caulk is the most common color, you can also find options in clear and tan. Use cartridge tubes if you need a wide variety of colors.

Frequently Asked Questions

Here are some answers to frequently asked questions about caulking bathrooms, showers, tubs, and sinks.

What kind of bathroom caulk is completely waterproof?

Most people assume that all caulking is waterproof, but that's not true. The purpose of caulk is to fill gaps in walls, floors, and ceilings. By doing so, it keeps out air and moisture, which can cause a variety of problems. Using the wrong kind of caulk can result in leaks!

Some bathtub caulking is made with latex, which will eventually degrade when exposed to water. Make sure the caulk you buy has a label that reads "waterproof" or "water-resistant". Unless it says either of these things on the packaging, the caulk should not be used near moisture.

Silicone caulk is usually preferred over latex caulk in bathrooms since it is 100% waterproof whereas an acrylic latex formulation is not. The waterproof quality of caulk is derived from its water-based adhesive and water-repellent filler. In latex caulks, the filler is usually styrene butadiene, which breaks down when exposed to water and cannot be relied upon for waterproofing.

What is the best shower caulk?

In a shower, silicone caulk is the best because it is 100% waterproof, highly resistant to mold growth and mildew, and will not shrink or crack. Additionally, silicone is easy to work with. You can choose it in several colors, even clear, to match the color of your bathroom's ceramic tile or grout. Also, silicone caulking stands up well to frequent cleaning and daily use. You can remove soap scum and hard water deposits with just soap and water.

Shower tile and grout are porous materials that require sealing. A good caulk will create an impermeable seal that extends into the tiniest cracks between the tiles and around the edge of the tub or a shower surround. As an inert material, silicone does not react with other substances at room temperature or undergo chemical reactions that would cause it to deteriorate. It is extremely durable.

If a caulk job is done correctly, it will last for years without a problem. Silicone sealant is the obvious choice when it comes to caulk longevity.

What is the difference between acrylic latex, acrylic latex with added silicone, and pure silicone caulk?

There are three types of caulk that you can use in and around your bathrooms, tubs, shower surround, and sinks: acrylic latex, acrylic latex with silicone added, and pure silicone.

Acrylic latex is normally the most affordable. It is commonly used to fill nail holes, small cracks, and small gaps in walls and floors. However, it is not very flexible and is not waterproof.

Adding silicone to acrylic latex makes it more flexible and water resistant, so it's slightly more expensive. It's an excellent middle ground between acrylic latex caulk and silicone caulk. It is a great choice for baseboards in high-humidity environments, and some types can even be painted.

Silicone caulk is the most expensive of the three types. It is extremely flexible and waterproof. The downside is that it can't be painted and it's generally difficult to use if you don't have much experience.

What is the best bathroom caulk to prevent mold?

A silicone caulk is waterproof, mold resistant, mildew resistant. Unlike other materials, silicone doesn't become brittle over time. It forms a tight seal that lasts for years. With silicone, you won't have to worry about caulk damaging tiles like you would with other materials. Waterproof caulk is commonly used in bathrooms and other areas where water is present.

Using silicone caulking in your bathroom is primarily because it resists mold and mildew if there are leaks or spills. A mold infestation in your bathroom would be awful.

If you plan on doing any DIY work in your bathroom, silicone caulk is ideal since it can be removed at a later date without damaging surfaces. In the event you decide to remodel your bathroom, remove the floor or walls, you can remove the silicone caulk without causing any damage.

You can find this at most hardware stores, home improvement stores, or online.

What happens if you don't caulk your bathtub or shower surround?

Sinks, tubs, and showers in the bathroom are among the most likely places for water damage in your home. When they are not properly sealed, water can leak out and cause many problems, from mildew and mold to more serious health issues like black mold. That's why you should keep your bathroom fixtures properly caulked.

Shower and tub caulk are inexpensive and easy to install. Maintaining your bathroom is absolutely crucial, especially if you have a bathtub or tub/shower combo. Taking care of the caulk before it becomes a problem can save you a lot of trouble even if you eventually experience some water damage.

How often should you caulk your shower or bathtub?

Caulk doesn't just keep water out. It also keeps water in. You need to keep in mind that even if you seal an area off with caulk, it needs to be waterproof. As long as the area is not sealed as tightly as it could be, the caulk will only delay the inevitable.

Caulking frequency depends on the climate where you live and on how well you maintain your bathroom. Many people choose to caulk every time they refinish their bathtub or shower, but caulking is usually only needed when there are cracks or gaps that allow water to escape. If you keep an eye out for cracks or gaps, you can caulk as needed instead of all at once.

The simplest way to clean your caulking is to use a toothbrush and some water to gently remove any dirt or grime you find. Dirt and grime can cause your caulk to lose its effectiveness, so it's a good idea to clean it once in a while. Keeping the caulk clean can help it last longer than it would otherwise.

How many tubes do you need to caulk around a bathtub?

It depends on how big your bathtub is and how many areas need caulking. A tub surround is the space between the walls, the floor, and the ceiling of a bathroom. Most tub surrounds are made of fiberglass, tile, or wood. There will be at least one seam where the tub meets the walls and another where it meets the floor. Leaks are most likely to occur at these points. Some tub surrounds also have seams where they meet the ceiling.

Seams in fiberglass tub surrounds are often held together with silicone caulk or silicone adhesive. The majority of wood and tile tub surrounds are constructed with a miter corner joint or corner bead that is nailed into place. It is important to keep these areas caulked as they are great entry points for water.

If your bathtub is finished with acrylic, you should probably caulk any joint where water can get in, including seams, hardware holes, and places where the finish might crack naturally due to stress. Additionally, caulk any joint that does not look completely smooth, even if it is not visible from the outside.

Should you caulk around your bathroom sink?

Caulking around a bathroom sink is often the first step to preventing damage to a countertop. This will keep water from getting underneath the sink and damaging the countertop as well as the cabinet. Unfortunately, most homeowners ignore caulking around their bathroom sinks, but it's an important step to take.

What caulk should you use for a bathroom sink?

There are many great bathroom sink caulk products available, but 100 silicone caulk is the best. Aside from being waterproof, mildew and mold resistant, and easy to clean, it's also long lasting. It can be used to seal around a bathtub or shower, or around a sink. The caulk will prevent water from leaking through so it doesn't damage anything behind it (assuming there are no gaps or holes in the caulking job). In addition, silicone caulk is easy to clean gently with a toothbrush.

How long does silicone waterproofing last?

Thin, flexible, rubbery sealants are used in bathrooms to prevent water from seeping into cracks and joints between tiles, marble, and other surfaces. Since silicone is waterproof and non-toxic, it is commonly used to fill cracks and gaps in these materials.

Silicone sealants last about 20 years on average. Temperature, UV light, exposure, and the chemical properties of the surface material influence the longevity.

Can you caulk over old caulk?

It's so tempting to caulk over existing caulk, but it's a bad idea.

The reason it is wrong is that the new caulk won't bond properly to the old caulk. This can cause leaks and mold damage.

So before you caulk, make sure to remove the old material first and then clean the surface.

You can remove old caulk with a caulk scraper tool, or a utility knife that has been sharpened to a razor edge. You can find these tools at almost any hardware store.

After removing all of the old excess caulk, clean any residue with a caulk remover such as mineral spirits. Any residue remaining on the surface will prevent the new caulk from adhering correctly. Be sure to test the area first before proceeding. Mineral spirits can damage many surfaces.

You can apply the new bath sealant the same way you did on the original caulk once everything has completely dried.