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Can You Caulk Over Grout? (Do This Instead!)

Caulk can seem like a fix-it-all solution when it comes to sealing cracks in your home. It’s great for windows, bathtubs, countertops – all sorts of things. But what happens if there’s already a sealant in place, like grout?

Grout is typically a mix of water, cement, and sand. Its most common use is to seal the gaps between tiles. It can last for years with proper care, but you may wonder if you can cover old grout with caulk.

You should not caulk over grout as it will not form a strong bond. At best, this is a temporary solution, as the caulk will soon peel away from the grout. Caulking over grout could also trap in moisture, leading to mold and mildew issues. It’s always better to start caulking on a fresh surface.

Caulk Vs. Grout – What’s The Difference?

Caulk and grout are both types of sealants, but each has its own specialties. Grout cures to a very hard finish, and it’s most commonly used with tile. Using grout between the gaps of the tiles seals them together tighter and creates a more even surface.

On the other hand, caulk is more flexible and is often used to seal cracks between two different surfaces. You’ll often see caulk around your toilet or bathtub, or even your windowsills.

Caulk is more flexible than grout and it can go in more areas, although grout does better in high-moisture spots. Caulk can go around the edges of bathroom fixtures, for example, but grout is better for the walls and floor.

If you’re redoing a shower, it might even be best to use a combination of grout and caulk.

Why You Shouldn’t Caulk Over Grout

In theory, you can caulk over old grout. But in practice, it’s not a good idea. To begin with, the caulk just won’t adhere well to the grout. This is especially true if you’re caulking to cover crumbling or cracking grout.

Caulk can shrink and peel away from even the best of surfaces over time. When that surface is grout, it will peel away even faster.

Because the adhesion won’t be very strong, you’ll end up with gaps in between the caulk and the grout. This gives room for mold and mildew to grow unnoticed.

This can also lead to moisture leaching beneath your tiles. You could eventually have destructive mildew and mold underneath where it’s much harder and more expensive to reach.

How To Remove Grout

If there’s an area in your home that you want to update, it’s important to remove any grout before caulking. If the grout is visibly crumbling, it’s possible to remove it manually. However, if it’s still intact, you’ll be better off using a power tool.

What You’ll Need:

  • Metal tool such as an awl or an old screwdriver (for manual removal)
  • Rotary tool with grout blade (for power removal)
  • Face mask
  • Safety goggles
  • Drop cloths
  • Flat head screwdriver

1. Prepare Your Work Area

Lay down enough drop cloths to cover the floor and any furnishing in your work area. Removing grout will naturally create a lot of dust and debris. This is also why you should wear a mask and goggles, as the silica dust can irritate your soft tissue.

2. Score Away The Grout (Power Tool Method)

If using a rotary tool, turn it on and apply the blade at a straight angle to the grout line. Don’t hit the tile, as the tool will remove it just as easily as it will the grout. Always follow the manufacturer’s instructions for power tools.

You only need to apply slight pressure to the grout; the blade will do the rest. Once you remove most of the grout, you can carefully angle your tool to get further back in the joint.

Use a screwdriver to knock away any remaining chunks of grout you couldn’t get with the rotary too. You may still have some pieces left that just won’t come away; if so, use the manual method below.

3. Scrape Away The Grout (Manual Method)

The manual method works well with crumbling grout, but even then, it’s a slower route than the power tool. However, if you don’t have one a power tool, you can use an awl or other pointed metal tool.

Dig your hand tool repeatedly into the joint between your tiles, scraping away the grout. It will take a long time, but it is doable.

If your tile is an easily scratchable material, take care to only scrape in between the joints. Just like with the rotary tool, if you’re not careful, you could end up damaging your tile. However, if you take it slow and steady, you shouldn’t have any problems.

4. Clean Up

Brush away any leftover dust from in between the tile joints. Afterwards, dump any debris that was gathered by the drop cloths into the trash. If some of the dust escaped the coverings, you can sweep it up with a broom.

Tips For Applying Caulk

Naturally, the best surface to which you should apply caulk is one that’s clean and free of any other sealant. This even includes old caulk, although it’s still a better surface than grout if you don’t have another option.

While you can caulk without a gun, it’s definitely easier to use one, and they won’t break the bank.

There are several different types of caulk, so be sure to use the one that suits your project the best. Most products on the market will list their uses on the label, as well as how to use them. However, you can also use the following handy chart for reference:

Type of CaulkBest Used For
SandedWet surfaces 1/8-inch or wider
UnsandedCountertops and backsplashes; joints less than 1/8-inch wide
Fast-DryingFast installation and painting
SiliconeWindows and bathrooms; outdoors; joints between two different materials
Acrylic/LatexWood, drywall, and masonry
Expandable FoamSoundproofing; pest-resistance; insulation
Butyl-rubberOutdoors only; heavy construction; gutters, concrete, and siding

In Summary

Applying caulk over grout will leave you with substandard sealing that will quickly peel away. It can also lead to mold and mildew that’s hard to reach. Eventually, you might have to pull up the full tiles to fix the problems.

Removing grout can be a pain since it’s such a sturdy material, but it can (and should) be done. There are a couple of different ways to remove grout, so you have options.

Then, once your joints are free and clear, you have options for your caulk as well. Choose something that fits well with your surfaces and their environments.

Instead of rushing through your caulking project, take the time to remove the old grout. Your project will look better and last longer.