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How to Recaulk a Tub

Updated
If you hate mold and mildew, rip out your old caulk and recaulk that bathtub.

Old bathtub caulk starts to discolor over time. Mold takes hold and stains the caulk, making your bathtub look grimy and less inviting. Do something about it before the problem becomes worse.

We show you how to recaulk a bathtub, including tips for the best results and how to prevent mold growth.


Best Caulk for a Bathtub

Always use an anti-mold caulk to repel fungal growth whenever you work in high-moisture rooms, like your bathroom. Several brands can do the job, but we liked this Gorilla Waterproof Caulk. It is mold resistant and is water-ready in just 30 minutes.

If this caulk doesn’t float your boat, why not try this InstaTrim Flexible Trim as an alternative to caulking. It is self-adhesive, requires no glue, and is easy to install.

Keep In Mind

Mold spores are damaging to your health when inhaled. They cause lung problems and can irritate asthma and other breathing conditions.

How to Recaulk a Bathtub

You’ve ignored your moldy caulk for too long, and today it gets its marching orders. Before you get down to business, you’ll need the right tools and equipment.

What You’ll Need

  • Caulk (mold-resistant).
  • Caulk gun.
  • Putty knife.
  • Razor scraper.
  • Utility knife.
  • Rags.
  • Paper towels.
  • Caulk remover.
  • Masking tape.
  • Mineral spirits.

Removing the Old Caulk

Before you can replace the new caulk, the old sealant needs to be removed. If you leave any trace of the mold, it will grow back and stain your new silicone.

1. Cut the Old Caulk

Use the utility knife to cut along the line of the old caulk between the tub and tile. Now switch your attention to the caulk where the tub meets the floor. Peel the old caulk away and dispose of it safely.

Repeat this process for the taps and drain stopper when replacing the caulk around the bath fittings.

2. Use Caulk Remover

Caulk remover, like this Goof Off Professional Strength Remover, works wonders on the stubborn sealant. It dissolves the caulk and quickly removes it from the tile and the bathtub.

Scrape the last caulk remnants with the razor scraper and wipe the surface clean with a rag.

3. Clean the Tiles

With the old caulk gone, clean the tiles and remove any loose grout. Spray mold remover, like this Mold Armor, to treat the stains on the grout and bathtub. Now, rinse off the mold killer with water and let it dry. You can use a hairdryer to speed up the drying process.

Use mineral spirits to give the surfaces a final clean. This Klean Strip Mineral Spirits is odorless and ideal for cleaning your bathtub before you caulk. Dab it onto a rag and rub it along the bathtub and tiles.

Word Of Caution

If you try to reseal on wet surfaces, you will trap moisture, and mold will grow.

Applying the New Caulk

Plumber applying sealant using caulk gun

With the old caulk gone, you’ll need to apply the new sealant. Before you do that, you’ll need to prepare the work area.

1. Use Masking Tape

This Scotch General Purpose Tape is perfect because it adheres well and is easy to remove afterward. Start by masking the corners first and then applying the tape along the gap between the wall and the bathtub. Don’t forget to do the same with the tub or shower floor.

2. Apply the Caulk

Look closely at the caulk tube, and you’ll see clear marks on the nozzle. These indicate the thickness of the caulk, so you’ll need to match your gap width with where you cut the nozzle.

Use the utility knife to cut the end off at the desired thickness and load it into the caulk gun. Starting from the corner, hold the gun at a 45-degree angle and squeeze the trigger. Pull the gun along the tub’s edge, ensuring that enough caulk fills the gap.

When you reach the end of the bath, release the trigger and flick the pressure release lever on the gun. This disengages the spring and stops the caulk from pushing out of the tube.

Take Note

Some people prefer to cut the nozzle at 20 degrees and hold the caulk gun at 90 degrees. They maintain that this forces the caulk into the gap, filling all the available holes.

3. Use Your Finger as a Tool

Starting at the corners, wet your finger and wipe it along the caulk line. When you reach the end of the caulk line, wipe the excess sealant into a paper towel.

4. Remove the Tape

Peel the tape away at a steep angle, ensuring that it leaves the caulk intact. Remove the tape in the corners last.

Top Tip

Always peel the tape away while the caulk is still wet. If it dries, you risk pulling the caulk with the tape or ripping the tape.

How Long to Let a Bathtub Dry Before Caulking?

You should wait for 24 hours before caulking your bathtub. If the tub hasn’t dried properly, moisture gets trapped beneath the new caulk layer, and mold grows.

As we’ve said, you could use a hairdryer to dry your bathtub to speed the process up or mop any water with dry towels.

Tips for Recaulking a Bathtub

Whenever you undertake a DIY project, getting the best advice is crucial for the end result. So, what tips can we offer to make caulking your bathtub easier? Let’s take a look.

Fill the Tub Before Caulking

Filling your bathtub with water before caulking is vital. It ensures that the tub sits at the correct level. Without filling the bath, you risk the tub sinking and pulling off the new sealant. Leave the water for 24 hours to allow the caulk to set with the tub at the correct level.

Use White Vinegar

If the thought of using chemicals to clean your grout fills you with horror, try taking the natural approach. White vinegar is one of several alternatives to harmful bleaches and chemicals. This ChemCorp 45 Percent Cleaning Vinegar is ideal because it has all the strength but is non-harmful to the environment.

You can either dab it on neat or mix it with water in a spray bottle.

Warm the Caulk

Place the caulk tube in a bowl of warm water to make it more pliable and easier to work with. It also helps the caulk adhere better and spread more evenly.

Don’t Stop In the Middle

If you stop in the middle, it leaves blobs of caulk that look uneven and messy. Start at one end and continue until you reach the other end. Apply gentle pressure to regulate the caulk flow.

Start in the Corners

Never start your caulk line in the middle of the bathtub. Always start in the corners and work towards the other end before stopping.

How to Prevent Mold Growth on Caulking

Mold loves moisture, so the best way to keep it from growing is to keep your caulk dry. After you bathe, wipe the caulk with a dry towel to remove water pools. Also, keep a spray bottle of white vinegar and water handy to coat the caulk every time you wash.

White vinegar is acidic and eats mold and mildew, so regular spraying prevents fungal growth.

Alternatives to Caulking Around the Bathtub

While the caulk is easily the most popular way of sealing our bathtubs and showers, it isn’t the only way. Let’s look at your other options:

Adhesive Strips

Adhesive sealant strips are an excellent alternative to caulk. They come in rolls with a peelable backing that adheres to your bathtub and tiles. Simply peel the backing away and press the flexible trim in place.

This NeatiEase Quarter-Round Flexible Molding is waterproof and provides a neat finish for bathtubs, showers, and sinks.

Epoxy Resin Sealer

Epoxy resin is waterproof, hard-wearing, and stands up to the rigors of bathroom use. This craft epoxy is ideal because it comes with a hardening agent to ensure it sets solid.

Sealant Tape

You might be looking for a temporary fix until you have the time and materials to perform a proper repair. Sealant tape, like this Gorilla Patch and Repair Tape, is waterproof, highly adhesive, and easy to apply.


Let’s Talk About Caulk

Knowing how to recaulk a tub is vital to help reduce the spread of mold. It keeps your bathroom in better condition and transforms stained and discolored walls.

Sealing a bathtub is easy to do, cheaper than other DIY repairs, and you can reuse the caulk on other projects to get your money’s worth. So, the next time your sealant looks neglected, whip out the caulk and get to work.

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About the Author

Mark Weir

Mark spent 24 years working in real estate, so he knows his way around a home. He also worked with contractors and experts, advising them on issues of planning, investments, and renovations. Mark is no stranger to hands-on experience, having renovated his own home and many properties for resale. He likes nothing better than seeing a project through to completion.