Best Caulk For Showers (To Prevent Mildew)

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Showering is one of the most efficient ways to stay clean but with the amount of water that is spread around in a typical shower cubicle, it is very likely that mildew can form and become a recurring problem. 

Mildew is a form of fungus that can have its growth promoted by the warm moist conditions of a shower.






Gorilla White 100% Silicone Sealant Caulk


Sashco Clear Lexel Adhesive Caulk


Loctite Polyseamseal Tub And Tile Adhesive Caulk


GE Silicone Clear Kitchen And Bath Silicone Caulk


Flex Shot Rubber Adhesive Sealant Caulk


Red Devil 0405 Duraguard Kitchen & Bath Siliconized Acrylic Caulk

The fungus does not cause immediate health problems, but if the spores do become airborne they can be inhaled by someone using the shower and can cause some health issues because you are essentially swallowing small quantities of mold over an extended period of time.

There are many ways to get rid of mildew once you can already recognize it is in your shower, and there are also different ways to attempt to stop mildew from forming in the first place (good ventilation is key).

But one of the best methods for preventing mildew from becoming a recurring problem is in the construction of the shower itself.

While assembling a shower from scratch is no easy task, one element of the design of a shower which is much easier for anyone to have control over is the caulking (see also ‘Alternatives To Caulking Around The Bathtub‘).

The caulk in between tiles and in the corners of the shower is one of the places where mildew is most likely to form.

Because of this, using a caulk in your shower that can resist and prevent the presence of mildew will save you a lot of time and can even prevent health issues if done well enough.

Having a caulk that is well suited for dealing with mildew is especially important if you do not have much control over being able to prevent mildew from forming.

A good example of this is a shower located in a room with no direct access to windows or a poorly functioning extractor fan.

Since these factors make it more likely that mildew will form, including an anti-mildew caulk is even more important.

Most mildew-resistant caulk is made from water-resistant silicone and could even include ingredients that are used in anti-mildew cleaners to make sure that the fungus does not begin to form.

So read on to see the types of caulk that are best to use in a shower if your primary concern is lowering the chances of mildew forming. 

Gorilla White 100% Silicone Sealant Caulk


For big projects like caulking an entire shower, this caulk is an amazing choice.

You will need a caulking gun to use this product, however, they are usually not too much of an investment and will make a big project like this significantly easier.

This caulk by Gorilla is 100% waterproof silicone making it the perfect fit for showers with it not absorb any water and does not providing conditions that promote the growth of mildew. 

Gorilla also boasts a speedy 30-minute drying time making this a great choice if you need results fast, however, this does mean you will need to work carefully as mistakes can become permanent quickly.

This caulk has been tested to have an amazing last time, many caulk, especially in showers, can yellow and crack after too much use and aging, but this product has shown minimal signs of these problems. 

This particular style dries white, but you can also get an alternative product by Gorilla that has the same properties, but dries clear if that will match the aesthetic of your shower more fittingly.


  • Long-lasting and durable
  • Clean finish
  • 100% waterproof silicone
  • 30 minute drying time


  • Quick-drying time can cause issues
  • Needs a caulk gun

Sashco Clear Lexel Adhesive Caulk

This caulk also has amazing durability and when tested with regular and consistent cleaning has shown minimal signs of wear.

When dried the Sashco Adhesive caulk has a uniquely elastic texture, but this means that the caulk makes particularly tight seals that do not separate from tile or crack. 

Preventing gaps like this is incredibly important for stopping mildew from forming as small irregular gaps like this where water and warmth can get trapped are perfect conditions for mildew forming.

This caulk also has a quick drying time making it, so your shower is not out of commission for too long while the caulk is drying. 

Sashco is also proud of how multi-functional this caulk is, so if you are looking for a caulk you can use after you are done with your shower this is a good choice as well, it is resistant against outdoor weather as well as being easy to paint over.

But do not forget how useful this caulk is for preventing mildew containing anti-mildew properties to stop any chance of the fungus appearing.


  • Quick-dry time
  • Flexible and long-standing seals
  • Multi-functional 
  • Camouflage clear finish


  • Requires caulk gun to use
  • Quick-dry time can make mistakes hard to get rid of

Loctite Polyseamseal Tub And Tile Adhesive Caulk

Like the Lexel, the Loctite Polyseamul caulk is also a great multi-use caulk for anything that needs waterproofing, but it really excels in use in showers, especially when it comes to preventing the growth of mildew.

The caulk is great at adhering to any surface meaning that no matter what material you have made your shower out of, this product will be able to make longstanding seals that prevent the chance of any mildew forming. 

This caulk by Loctite also makes sure to emphasize the inclusion of ‘mildewcide’ ingredients in the caulk that are harmful to mildew making it very hard for the fungus to make its home in your shower.

And being so flexible and durable you can be sure that these anti-mildew seals will last for years. 

Also, a problem that a lot of caulks face after being installed is a chemical-like odor that can become particularly overpowering once the shower has been turned on.

However, this product has been designed to have a very minimal odor after it has finished drying, so you will not have to worry about this issue after you have finished installing. 

A final unique factor that helps this caulk stand out is that you do not need to use a caulk gun to get good results only needing to snip a little hole at the top of the nozzle to get a consistent stream of caulk just by squeezing.

While using a caulk gun is generally considered easier and can lead to more uniform results after the caulk has cured, it is an extra investment, and if you do not want to learn to use a new tool, a caulk like this is a great choice.


  • Does not need a caulk fun 
  • Great flexible and durable seal
  • Anti-odor design
  • Mildewcide ingredients to prevent the growth of mildew


  • Will not fit a caulk gun if you prefer this method.
  • Not an extra-quick drying time.

GE Silicone Clear Kitchen And Bath Silicone Caulk

While not having the super quick drying times of some of the other brands mentioned, the GE Silicone caulk can be used after just 3 hours.

But more impressive than this is the guarantee made by GE that this caulk (if correctly applied) will remain free from mold and mildew for 5 years. 

This caulk is 100% waterproof as well as flexible meaning that the seals it creates will be longstanding and not easily broken.

Having a high silicone content also makes this caulk incredibly resistant to the damage that can be caused by UV rays as well as heat-resistant.

This also makes it great for dealing with fluctuating temperatures meaning it works just as well in heat as it does in the cold.

This product also comes in packaging that does not need a caulk gun to use.

This means that while this product can work well on smaller projects and does not need the extra investment of a caulk gun, if you have a caulk gun and want the extra control, this product does not offer it.


  • Reasonable dry time
  • 5 years guarantee without mold or mildew
  • Does not need a caulk gun
  • Strong adhesive


  • Not compatible with caulk guns if you want that extra level of control
  • Not great if you want a super quick dry time

Flex Shot Rubber Adhesive Sealant Caulk

The Flex Shot rubber adhesive caulk is another choice that does not need a caulk gun to work making it a great choice for smaller projects and perfect if you are a beginner when it comes to caulking.

This is also one of the best choices for a strong sticking bond with the flexible seals made by this caulk almost unbeatable.

The bonds made by the Flex Shot are completely watertight and because of this it is a great choice for tackling mildew.

Even though you can not use a caulk gun with this product, the canister of the caulk is designed to give a similar feel to a caulk gun to make the product as mess free as possible and to make sure that the bead of caulk does not get stuck in the wrong position.

Using this product  is just as easy as using a caulk with a caulk gun making it a perfect choice for if you want this extra level of control without having to invest in another product. 


  • Incredibly durable caulk which will not need to be reapplied often
  • Easy to use canister for great level of control
  • Dries quickly
  • Completely waterproof


  • Not compatible with a caulk gun
  • Leaves a strong odor which can take a while to wear off

Red Devil 0405 Duraguard Kitchen & Bath Siliconized Acrylic Caulk

This product stands out from the other caulks on this list as it is not 100% silicone containing some acrylic making its contents a siliconized acrylic.

Even though this product is not using just silicone, the inclusion of acrylic makes the caulk even more durable and a better adhesive.

The caulk also has a flexible adhesive which as established is a perfect choice for showers. 

It has a nice smooth finish as opposed to some of the lumpier less consistent caulks making it easy to get aesthetically pleasing as well as effective results.

The smooth finish also makes it extra resistant for preventing mildew forming as well as mold. 

This caulk also has the extra bonus of being almost completely scentless unlike a lot of the other choices that can make a strong smell.

This caulk is also super easy to clean if you put some in the wrong place before it dries.


  • Great smooth finish available in multiple colors
  • Easy to apply and clean before it has dried
  • Perfect for smaller repairs but usable on bigger projects
  • Good for preventing mildew and mold


  • Not being 100% silicone stops it from being completely waterproof
  • Not compatible with caulk guns

Buyers Guide

Does It Need A Caulk Gun?

This is a quick and easy characteristic of the caulk you are using to identify with nice and clear pros and cons.

You can tell if your caulk is compatible with a caulk gun based on the shape of the container.

If it is a tougher tube which has a base which looks like it can be pierced, it is compatible with a caulk gun and this is the best way to use the product.

If the caulk is in a container which is made of a softer squeezable material and just a nozzle at the top, this product does not need a caulk gun to use. 

If you have a caulk gun, of course, getting a caulk that can be used with a caulk gun is preferable.

But if you do not own a caulk gun, getting a product that does not need a caulk gun is better. 

If you are on the fence, a caulk gun is usually not an expensive purchase and gives you the best level of control with caulking.

However, if you think this is a one off, and you will not be caulking much afterwards, investing in a caulk gun will probably be a waste.

How Quickly Does It Dry?

While this step does not usually affect  the final performance of the caulk, it does influence how painless the process of installing the caulk is.

Some caulks can be ready in minutes while others recommend waiting a day after installation.

Getting a quicker drying caulk means you can use the area you are caulking sooner after caulking, but this also means that you will have to be much more careful to not make any mistakes when installing the caulk. 

Also, it is generally recommended to leave the caulk to dry longer than packaging recommends just in case external causes have slowed the process.

Putting running water on undried caulk can lead to disastrous consequences as well as a waste of time and money.

Final Dry Color?

This is an easy variable to check, but if you get a caulk that will not dry in your desired color, while it generally will not affect the results, you will have a very ugly final result.

For example using a clear finish caulk with an ugly backing can look very bad, while using a bright white can stand out in a very unflattering way if it does not match the tiles.

Just make sure to get a matching color, and you should be fine.

Best Caulk For Showers (To Prevent Mildew)

What Is It Made Of (Waterproof And Mildewcide)

If you are getting a caulk for a shower, make sure to check what the caulk composes of and if the manufacturers mention if the product is designed to be waterproof and prevent mildew.

You can learn what components will affect these factors like a high silicone content being waterproof and ‘mildewcide’ ingredients helping stop the growth of mildew.

But if these are not mentioned, it is best to avoid that caulk for a shower.

Having a caulk without these qualities installed in a shower can actively promote the growth of mold and mildew.

Final Thoughts

So now you know all the different types of caulk that will work best in a shower for helping take preventative measures against the growth of mildew and mold.

Keep in mind all the factors in the buyer’s guide when choosing a product that you will use.

If you want to make sure mildew does not form, make sure your caulk is well applied and fully waterproof.

Also make sure to keep the shower well ventilated after use to help the caulk last longer.

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