Why Is My Bathroom Grout Cracking? [And How To Fix That]

Most of us have a regular bathroom cleaning routine, and you tend to notice when parts of the grout aren't looking too healthy. But what causes bathroom grout to crack? How do you fix it? Well, we've delved into the research and have several informative answers for you!

Floor and shower grout begins to fracture for various reasons. The top culprits are general age, joint movement as the house settles, and improper mixing or installation. If the cracks are small and isolated, you can often do a simple patch repair yourself. However, if the fissures are extensive it is recommended to call in professionals to avoid further damage.

So, how do you fix cracks in bathroom grout? Can cracks in shower grout cause leaks? Does grout sealer prevent cracking? Continue reading to learn how to manage your sealant issues and protect your bathroom!

Home improvement background,close-up of a tile setters hand applying tile grout with a grout float to a new tile shower wall. Why Is My Bathroom Grout Cracking [And How To Fix That]

Causes of cracked grout

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Causes of cracked grout

There are several sources can that lead to deteriorated bathroom grout. Let's jump right in and look at the major reasons your sealant is damaged!

Wear and tear

Simple age can often cause sealers to degrade. Our bathrooms are constantly exposed to moisture. They also have regular fluctuations in temperature and humidity. Traditionally, grout is composed of sand, cement, and water. Since the product is porous, the damp environment degrades the grout over time.

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Dirty grout with beige tiles in a bathroom with black mold, spores, rust and soap residue that needs to be cleaned.

Lack of proper cleaning and regular maintenance worsens normal wear and tear. If allowed to accumulate, soap scum and hard water minerals can cause erosion. This can lead not only to splits but also toxic molds. Ideally, bathrooms should have a good scrub down weekly. Add a thorough visual inspection for problems, as well.

Joint movement

Collapsed house structure problems with cracked floor tiles

All houses experience subtle shifts as time goes by. It also naturally occurs during seasonal temperature changes. As the foundation and joints settle, inflexible grouts can be damaged. This happens when the tile floor or wall shifts in one direction but the tub goes in another. You can also see this around other bathroom appliances, depending on their location.

If you live in a part of the world that experiences earthquakes, joint movement can become an even larger problem.

Improper mixing or installation

worker hands are mixing concrete in a bucket at a construction site. Mixing cement or mortar with Electric drill.

Proper preparation is crucial to an effective grout. When the mixture contains too much water or additives, air pockets sometimes occur. This can also happen if too little adhesive glue is used. These make the sealant weak and prone to damage. Once an initial crack occurs, more serious ones tend to follow.

It's important to have a professional installation of tile or brick grouting. Knowledge is required in order to avoid the many things that often go wrong during the process. The cracking of badly installed sealant will eventually lead to serious structural deterioration.

Can cracks in shower grout cause leaks?

Sealing the cracks of tile from moisture and dust

Holes and cracks in your shower grout will lead to leaks if left unfixed. This is especially true when the tiles also start to break or separate. If this happens, you shouldn't ignore it.

The buildup of moisture inside fissures creates the perfect conditions for black mold. This particular toxin is extremely hazardous to the health of your family. Negative effects of exposure include headaches, difficulty breathing, depression, and neurological issues.

Water damage from leaking compromises the structural integrity of your bathroom, as well. Your walls and flooring are at extreme risk at that point. Do your best to correct the situation immediately if you wish to prevent costly damages.

Does grout sealer prevent cracking?

Homeowner uses toothbrush and grout sealer to paint tile grout lines

Grout sealant adds an extra barrier of protection against water, stains, and mold. That being the case, it is beneficial to apply it. A quality sealer will lengthen the lifespan of your grout and lower the chances of cracking. We recommend doing this every two years for optimal results.

Note that if you have epoxy-based grout (often used in glass tile installations), you should not need additional sealant. Epoxy is more water-resistant and flexible by design. However, you find it more in kitchen use.

Grout sealers are simple to apply yourself, though somewhat time-consuming. You can spray it on or use a paint roller. They're generally inexpensive, especially compared to the repair bill for a water-damaged floor. More money in your pocket!

Click here to see Aqua-X Clear Grout Sealer on Amazon.

Click here to see StoneTech Heavy Duty Grout Sealer (liquid) on Amazon.

How do you fix cracks in bathroom grout?

Caulking the bathroom tile, using painters tape

When you find problems with bathroom grout, you have multiple options depending on the severity. Let's go over them!

Patch it

If you're only dealing with a small number of pinholes, you can usually patch it up yourself. Although conditions vary, here are some basic steps to take:

  • Grab a tube of pre-mixed tile grout in the appropriate color.

Click here to see Pre-Mixed Tile Grout Squeeze Tube on Amazon.

  • Following the instructions on your grout, push it into the holes.
  • Use a wet sponge or cloth to wipe off any residue that landed on the tile itself.

Again, this method is only good for tiny pinhole patches. For larger issues, continue reading!

Try silicone caulk

Caulk Gun Applying Silicone to Granite Sink Backsplash

If you're dealing with slightly bigger cracks or holes in isolated spots, you can attempt the silicone caulk method.

  • Scrape out all the old grout in the problem spots.
  • Use a hand vac and sponge to clean the area well.
  • Pick a tube of waterproof silicone caulk that matches the color you need.


Click here to see Gorilla Silicone Sealant Caulk on Amazon.

  • Make sure you have a caulking gun to apply the silicone with.

Click here to see Bates Caulking Silicone Gun on Amazon.

  • Follow the caulk's directions to fill in the grouting gaps.

If you haven't worked with silicone before, you might want to try it on some scraps first. It dries extremely fast, so it can be tedious for the inexperienced. Keep the area well-ventilated to avoid the fumes.

Replace it all

For dealing with larger areas or completely broken grout, more effort is required. However, you can definitely still DIY this (if you want to)! We'll give you a brief overview of the process.

  • Use a sharp tool to remove the old, crumbling grout in the affected area.
  • Vacuum the cracks thoroughly and wipe down any dust with a moist cloth.
  • Purchase a tub of pre-mixed tile grout in the desired color.

Click here to see Pre-Mixed Tile Grout 1QT on Amazon.

  • Use a grout float to spread the mixture evenly over the joints. Hit it from all directions.

Click here to see Goldblatt Rubber Grout Float on Amazon.

  • Scrape off the excess, wipe the area clean, and let cure according to directions. The curing will most likely take 24 hours.

Call for backup

Grouting ceramic tiles. Tilers filling the space between tiles using a rubber trowel.

Some of us simply don't have the time or expertise to correct these issues ourselves. Or maybe the job is outrageously complicated. Perhaps you're concerned about underlying damage. When this is the case, there's absolutely nothing wrong with bringing in the pros. Although it's an expense, sometimes it's worth it!

How do you fix cracks in shower grout?

Man's hand with trowel while grouting ceramic tile

It is highly recommended to hire a professional to repair damage to shower grout. There could already be a corruption of the wall or joints underneath that you may not be able to see. However, if you're set on doing it yourself, it is doable. The steps are somewhat similar to (but more complicated than) the previous instructions we listed.

Check out this Repairs101 tutorial for a full walkthrough on replacing shower grout!

Wrapping things up

So, we've established that cracked grout has several causes. Joint movement, age, and improper installation can all contribute to the issue. In order to fix it, you can either apply a patch or call out the pros.

Now, get out there and have a 'grout' day!

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