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


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Porcelain shower base in a bathroom

Damaged bathroom grout is something that you should never leave unattended. Having your grout cracked pretty much negates the main reason it is there, which is all the more urgent in the bathroom. Grout can help protect your tiles and the substrate underneath from water damage. Cracked grout can lead to more severe damage if left unresolved. As such, immediate repair is needed. But how exactly did your grout start to develop these cracks?

Grouts crack and fracture due to a wide variety of reasons. From wear and tear to joint movements and improper mixing and installation. All of these can factor into the overall durability of the grout. Therefore, if you notice cracks on your grout, it is best to take the necessary steps to fix this issue asap. 

Fortunately, there are numerous ways to fix cracks on the grout. However, we highly recommend you fix this problem quickly as it can lead to more severe damages that could quickly burn a hole through your pockets.

Reasons That Causes Grouts to Crack

Below are the leading causes of why grouts tend to crack and fracture. The good news is that you can take steps to prevent this from happening, or at the very least, prolong the problem from popping up.

The Cause: Wear and Tear

Wear and tear can degrade the overall durability of your grout. This is a fact, and while you can slow down the process, there will come a time when re-grouting the tiles will be needed. In addition, the constant exposure to moisture as well as chemicals from cleaning products and toiletries will also lend to the decrease of the grout’s durability.

The Fix:

With proper care and maintenance, you can prevent wear and tear damage from appearing too soon on your grout. Make sure to clean your bathroom tiles at least a couple of times per day. Rinse the soap and shampoo scum from the tiles after taking a bath and have a mold and mildew cleaning solution on hand.

The Cause: Joint Movement

Houses tend to expand and contract based on the climate and temperature of the area. This is why floorboards and doors tend to creak at night as the structural joints of the house contract. Unfortunately, this joint movement can also cause the grout to loosen and fracture over time. Cement-based grouts are rigid and will often be the first to take a hit due to joint movement.

The Fix:

Alternatively, you can opt to use epoxy-based grout, which is more durable and flexible than the standard cement grout. However, consider that epoxy grout is significantly more expensive than its cement-based counterpart.

The Cause: Improper Grout Installation

Another major cause of grout cracking is improper installation. For example, if you put too much water into the grout mixture as needed, you will be left with a pretty subpar grout to work with that will most likely not even last a whole year.

The Fix: 

The solution for this particular problem is pretty straightforward. Install the grout properly or have a professional do it for you. Of course, hiring a professional to apply the grout will add to the overall cost, but you will have peace of mind that the grouting is done correctly.

How to Fix Cracked Grout

If you are looking for a DIY fix for grout cracks, continue reading below. Of course, you will need specific hardware tools for this job, but overall, this guide is pretty simple to follow that even those with little knowledge in home improvement can accomplish. Also, note that this fix only applies if the gaps between the tiles are only about ¼ inch wide or less.

What You Will Need:

  • Utility Knife
  • Cloth
  • Portable Vacuum Cleaner
  • Blowgun Nozzle
  • Dremel Tool
  • Grout Saw
  • Matching Caulk and Caulk Gun
  • Safety Glasses and Hearing Protection

Fixing Cracked Grout Using Caulk

Once you have all the necessary tools for the job, you can begin fixing up that battered grout. Here is a simple step-by-step guide on how you should approach fixing a cracked grout.

Step 1: First, you will need to remove the damaged grout. Sad to say is that there is no easy fix for this type of problem. You will need to remove the grout and re-apply a new one. Use your grout saw or the Dremel tool and carefully chip away the grout.

Male hands with knife removing the old grout.

Step 2: Once you have thoroughly removed all traces of the previous grout, clean the area by having a vacuum cleaner do a couple of passes to remove the remaining debris.

Step 3: Carefully apply the caulk between the tiles using the caulk gun.

Step 4: Carefully press and smoothen the caulk using a plastic spoon.

Step 5: Let the caulk dry for at least 48 hours before having anyone use the bathroom.

Plumber fixing toilet in a washroom with silicone cartridge

Grout cracks can lead to serious problems if left on their own, and the causes can vary for each case. However, repairs tend to be pretty straightforward, as you can see from our simple DIY guide above. Also, if you are not confident in your skills and wish to ensure the best possible results, we recommend you hire a professional to do the repairs instead.