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Many people don’t know that you can actually caulk over old caulk, but it’s not the best idea. Caulking can be a great way to fix up your home, but if you have an old layer of caulk on your shower window or other surface and want to cover it, up-it is not recommended by professionals.

Caulking is a very common type of project that can enhance the appearance and value, but it can also be very messy. Caulk can’t usually be replaced without removing previous layers first.

 

What is Caulking?

Caulking is a material you usually use to fill the joints between tiles, grout, or bricks to create a seal. This prevents water from getting into the joints and causing damage to the surface.

A common misconception is that caulking over old caulk is a good idea because it will cause the old caulk to harden and dry out. In reality, this only happens in rare circumstances where the old caulk was of poor quality or applied incorrectly. It also doesn’t typically happen if there’s a significant difference in age between one side and the other sides of an application of new caulk.

Caulk Over Old Caulk

Can you caulk over old caulk?

Yes, you can caulk over old caulk, but it isn’t a great fix.

If the caulk was initially applied correctly, a new layer could indeed be added without causing damage to previous layers. It could be a challenge if the caulk was applied incorrectly, however.

If you can’t remove the old caulk layer, it’s best to clean that area and let it dry out completely before adding the second layer of caulk. If possible, scrape off any loose chunks with a putty knife or paint scraper to allow the new caulk to adhere more effectively.

Removing Old Caulk

Caulking can be a great way to fix up your home, but if you have an old layer of caulk on your shower window or other surface and want to cover it, up-it is not recommended by professionals.

Pro Tip! Caulk can’t usually be replaced without removing previous layers first, but if you’re going for a patchwork look, this is something you can do. Just make sure that all of your caulk is completely dry before applying any paint or coating.

 

What does caulk do?

What caulking actually does is limit the movement of water within joints, which helps slow down internal damage caused by condensation and moisture getting in through the hidden parts of a building. This is one reason why you’ll see people who have rotted wood siding or other building materials along the exterior of houses that look good from the outside but are structurally unsound. They likely had old caulk covering the joints, and it prevented damage inside of the house from getting worse for an extended period of time, but eventually, that stuff gets wet enough to rot out.

 

What are the different types of caulk?

A few different types of caulk exist, but it really comes down to three main categories: silicone, acrylic, and polyurethane.

Silicone

Silicone is a flexible material you can use for applications where joint movement might occur over time, such as cabinets or window frames. It’s great for large joints but not so much for small ones.

Polyurethane

Polyurethane is more rigid in comparison to silicone and is ideal for smaller joints that aren’t susceptible to movement. It can also be used in applications where silicone would dry out and become loose over time, like the lip of a bathtub or other area that might get moisture underneath it.

Silicon and polyurethane caulk are used around wet surfaces like toilets, bathtubs, showers, and sinks. Their flexibility allows them to make a complete seal when applied properly.

Acrylic

Acrylic caulk can be used in applications where it is important to prevent moisture damage but can also look good and be easy to use. In addition, the caulk can be painted over the course of a couple of days so that you can get your desired paint color.

Acrylic caulk is used for interior joints where you can’t see it, like under cabinets, indoor rooms, and windows. It can be used on exterior applications as well, but it can become discolored by the sun. If you want to paint over acrylic caulk, allow a few days for it to dry completely before applying your first coat of paint.

 

Caulking Over Old Caulk: 3 Steps In Detail

If you decide to caulk over old caulking in your bathtub (or shower), here is what you need to do.

Clean the area

Before you can caulk over old caulk, you need to make sure that the old caulk is securely in place and clean out any debris, hair, soap scum, dirt, or other grime. If not properly cleaned, you can get moldy caulk on the old and will need to redo the caulking job.

Cleaning silicone caulk

If you have silicone caulk, you can use a 10 cup warm water to 1 cup bleach solution to remove any stuck-on grime. Don’t use soap and water on the silicone as it will leave a soapy residue, and you will not get a strong seal with it. You can use denatured alcohol if you want to clean it with something other than bleach.

Cleaning acrylic caulk

You can use soap and water on acrylic caulk. Make sure you remove any flakes or chips. Do not use denatured alcohol as it will damage the old acrylic caulk, and you will end up needing to remove it.

 

Give the surface time to dry.

Once you have cleaned the old caulk, let the surface dry completely. This will almost always take at least a day to happen, so scheduling this on your weekend is best. This is the best way to prepare the surface for recaulking.

Avoid using paper towels to dry it faster; it may leave some little pieces behind. Best to let it air try.

 

Apply caulk

Once you’ve made sure that the surface is clean and dry, it is time to apply the new caulk. 

First, you will apply the new (second layer) caulk over the old caulk. To do this, you will need to put the caulk tube in the caulking gun and cut the end with a utility knife.

Run the caulking gun smoothly at a 45-degree angle. Apply steady pressure as you apply the caulking, layering where the new caulk meets old and continuing to overlap layers on each side.

Always make sure that your new seam is wider than the old one so you can have a nice clean, finished look when you are done. 

Ensure that the new bead of caulking covers both sides and covers the entire edge of the old one for proper adhesion. If it doesn’t cover the old layer of caulk entirely, it will not stick.

Press the caulking against the surface using your finger to smooth it out; you should be able to feel it go over any ridges or bumps in the old caulk and should fill in all of the gaps. If there are air bubbles, you may need to apply more pressure after letting the area.

Apply a bead of caulk along the bottom of the section you want to re-caulk, using the utility knife to finish up and get a smooth edge. Then move on to another area of the bathtub that needs recaulking. For seams in corners and around fixtures like faucets, use a caulk ‘puck’ or putty knife to apply sealant where needed–just be sure not to overfill. The best type of caulking around a bathtub is the silicone kind. Silicone caulk will not shrink and become brittle over time like other kinds, which means it won’t crack or peel off easily. Plus, you can find silicone caulks in a range of colors, so they blend with your bathroom decorations beautifully!

applying caulk over old caulk

When not to caulk over old caulk

Remember: Caulk is not just for cosmetic purposes.  

If it’s cracked, peeling, or cracking off, then your old caulk could be allowing water to get into your walls or woodwork, causing mold growth and damage to the structure. Therefore, it is in your best interests to replace any old caulking that you find while doing an inspection of your home before having a professional home inspection.

There are few instances when you should never caulk over old caulk, and these instances relate to the sealant itself. These instances include if it has turned black due to mildew or mold growth, if it’s more than a couple of years old, or if the base substrate (the surface it’s applied to) is peeling or severely deteriorated.

The bottom line: broken caulk, moldy caulk, and cracked caulk, you will need to remove it and put a fresh bead on it.

 

Best way to deal with old caulking

If you have old caulking around a bathtub, the best thing to do is remove it. The problem that most people have is that they opt to buy a tube of caulk and apply it over the old stuff. The results look more like an odd skin disease than a bathtub, and there are many reasons for this.

The first reason you will want to remove all old caulking around your tub or shower is that it just doesn’t look right. When you caulk over old caulking, the texture changes, and it is not an attractive option for anyone who cares about their home.

Another reason why you should clean up your bathtub or shower area involves water damage and mold issues that will usually occur underneath old caulking in a tub or shower. The old caulk doesn’t allow new moisture to dissipate, so it sits there and causes other issues.

Read our post for more on caulking a bathtub for complete instruction on how to do it. 

 

Can you caulk over the old caulk FAQ

Can you put a second layer of caulk?

You can add a second layer of caulk. However, you need to make sure the area has been cleaned and properly dried. When applying the second layer of caulk, it must coat the whole first layer and touch the surfaces on either side of the caulk to ensure adhesion and a proper seal.

 

Can you touch up the caulk?

Yes, you can touch up and repair areas where the caulk has dried or cracked. You can get a can of new caulk at your local hardware store and patch it in the needed area to fix it. By using another coat of caulk over an old dry layer can cause issues down the line and can be very difficult to repair. Caulk can last for years. However, it can still crack, and if you can see the white of the caulking, then it’s time to replace it.

 

Can you apply silicone over new silicone?

It is best to remove the old silicone as nothing sticks to silicone, and it will create water issues, like black mold, later.