Common Two-Tube Epoxy Grout Sealant Application Issues: How to Fix/Avoid Bubbles, Cracking, and Fall Off

Joining tiles traditionally required filling the gap with cement grout, which dried through evaporation. With epoxy grout sealant, the curing happens through chemical reaction. It fills the gap but essentially welds the tiles together, making it permanent but 100% waterproof. The result is aesthetically pleasing tiles, a foundational step in interior design.

To ensure everyone can achieve the exquisite look, manufacturers have now come up with the Two-Tube (Dual-Pipe) Epoxy Grout Sealant, making it a preferred choice amongst homeowners and professionals. The key factor for its popularity is the pre-mixed solution, which is convenient to apply using a caulking gun.

However, during applications and with the availability of the best tools, mistakes do happen. So during installations, if you have noticed bubbles, cracks, or peeling in your grout, these are some of the common issues that can be fixed. In this article, we will guide you on how you can fix these problems, why they occur, and how you can prevent them from occurring in the future.

1. Advantages of Using Dual-Pipe Epoxy Grout Sealant for Construction

Before we move on to the fixes, it's important to consider why using dual pipe epoxy grout sealant for construction is amongst the most popular choices for homeowners. In a traditional epoxy grout, mixing is messy with inconsistencies, whereas the dual-pipe system offers a clean, automatic solution.

• Automatic Mixing: One of the greatest advantages of dual pipe grout sealant is that you don’t require manual mixing with a drill paddle. The dual cartridges contain resin and hardener separately, so once you squeeze the sealant out through a spiral nozzle, the mixture comes out perfectly in a 1:1 ratio.

• Zero Water Absorption: Once cured, the sealant forms a hard barrier that resists oil, water, or any other general liquids, making it perfect for use in bathrooms and kitchens. 

• Decorative Finish: The final look of epoxy grout is smooth and furnished, with some options offering glittery or matte colors to further enhance the aesthetics of the overall space.

2. What You Need to Know About Common Epoxy Grouting Problems

Let's move on to some of the problems that users commonly face when applying epoxy tile grout. Below are mentioned the 5 most common problems with their solution and prevention tips to ensure the tiles are bonded and sturdy enough with enhanced durability.

1) Air Bubbles in Epoxy Grout Sealant

One of the most annoying problems when applying epoxy grout is tiny pinholes or bubbles coming up at the surface. This not only ruins the overall aesthetics but also reduces the overall structural strength, creating durability problems and surface irregularities.

• Why Does This Happen?

The primary reason why bubbles or air pockets appear is due to the air being trapped in the grout. This happens when there is air already in the tubing, or the caulking gun is moved too fast, which gives little time for the air to escape, hence creating air pockets under the sealant. By far, the most common cause is due to the moisture trapped in the tile gap. So when epoxy grout is applied, it heats up as it cures, turning water into vapors, which escapes creating air bubbles.

• Epoxy Grouting Solutions 

The easiest fix is when the grout is still wet. You can just pop the bubble with a toothpick or a needle and then reapply epoxy grout in that area by adding tiny drops and then smoothing it out. However, if the grout has dried out and hardened, instead of just filling it over, get a heat gun to soften the area, scrape out the old hardened section, and reapply.

• Prevention Tips

To prevent the problem of trapped air, discard the first 40cm of epoxy and then start applying it, as the air is mostly trapped on the top of the tube. To prevent the moisture problem, ensure that you use a hot air gun or hair dryer to remove any trapped moisture before you start applying the epoxy grout.

2) Epoxy Grout Sealant Shrinkage and Cracking

The main purpose of epoxy grout sealant is to hold the tiles together. If the sealant cracks or shrinks, the seal is no longer waterproof and allows moisture and dirt to seep into the tiles. 

• Why Does This Happen?

This mainly happens due to 3 main reasons: tile movement, solvent evaporation, and wide gaps. If the tile isn’t fixed properly and is loose, or due to uneven flooring foundation, uneven stresses develop, cracking the epoxy. Furthermore, if the gap between the tiles is large, greater than 5mm, the chances of shrinkage and cracking increase. One of the most overlooked reasons for cracking is due to using a low-quality epoxy sealant that contains heavy solvents. If these solvents evaporate, cracks start to appear.

• How to Repair Cracks

Repairing these cracks isn't as simple as just reapplying epoxy grout. These cracks usually appear once hardened, and the tiles are in use. To repair these cracks, you need to soften the old epoxy using a heat gun and remove it with a hook knife. Remove the dust and old epoxy remains and reapply a fresh epoxy sealant in the gap.

• Prevention Tips

These cracks can be prevented if the measures are taken before the joining process. These measures include checking if the ground is uneven by keeping a tile on the floor and walking on it. Make the ground even, then fix the tiles with epoxy grout. To prevent the problem of shrinkage, use silicon in some of the joints to allow the floor to move or expand during temperature changes.

3) Repairing Discolored Tile Grout

Epoxy Grout offers an excellent surface finish and is known to blend well with the overall aesthetics of the space. If it starts to turn yellow or dark spots start to develop, it can destroy the overall look of the space.

• Why Does This Happen?

The most common reason behind the grout turning yellow is exposure to the sun during the curing process. This results in epoxy grout reacting with UV rays and turning yellow. Furthermore, if harsh chemicals are used for cleaning tiles, the bleach or acidic cleaners can easily damage the grout before it has fully cured. During the curing process, if the grout isn’t protected from dust, these particles can permanently stick to the grout, which results in visible dark spots.

• Tile Grout Discoloration Repair

The repair depends on how much damage there is. If the decoloration is just on the surface, an epoxy cleaning spray would do the job. But if the decoloration is deep and the whole epoxy has become yellow, a grout colorant pen would be enough to provide a temporary fix, but for a permanent fix, removing the old grout and reapplying a newer grout that is UV resistant would be necessary.

• Prevention Tips

Don’t use chemicals that are too strong or acidic; go towards neutral detergents for cleaning. Lastly, to prevent yellowing from UV rays, use a UV-resistant epoxy or cover the room with curtains to block sunlight, which prevents fresh grout to react with UV light.

4) Epoxy Grout Sealant Peeling Off

If the tiles start to lose their space, and the grout starts to peel off like a plastic strip, it's most likely due to a weak bond between the sealant and the tile, often known as adhesion failure.

• Why Does This Happen?

This mostly happens if the base surface of the tile isn't cleaned properly. Epoxy bonds with the surface it's applied to. If the base surface has dust, moisture, grease, or wax, the epoxy doesn't bond properly.

• How to Fix Dropped Grout

If the epoxy tile grout is starting to peel off, it's better to remove it entirely. Clean the gap thoroughly and dry. After that, reapply epoxy grout to ensure the tiles stay safe and secure.

• Prevention Tips

The main reason behind the sealant peeling off is improper cleaning. Do ensure that before applying epoxy grout, clean the grout with alcohol or any solvent that can remove wax or grease, and then use a hair dryer or heat gun to ensure no moisture is left, after which apply the sealant.

5) Ripple-like Appearance on Grout Surface

The application techniques matter a lot when it comes to applying epoxy grout for joining the tiles. The grout line should be smooth, but if the lines are more like ripples or waves, it is most likely a problem of application technique.

• Why Does This Happen? 

The waves are mostly created due to uneven pressure when applying epoxy grout through a caulking gun. When applying epoxy grout, temperature does matter because if the weather is cold, the grout gets thick and adds resistance, making the application process slower. During the application, once the grout is applied, it starts to harden, and if pressed too late, the skin will wrinkle.

• How to Fix It

The curing process is based on two situations: if the wrinkles start to appear during the application, immediately wipe the tool and run it over the line again, but if the epoxy grout has fully cured and hardened, the most suitable option will be to sand it down to smooth it out.

• Prevention Tips

To prevent resistance during the application process, warm the epoxy tube in a water bath to 50°C before using to ensure a smooth flow. To prevent ripples or waves, it's important to move the gun at a steady speed to apply epoxy grout in a straight line.

3. Professional Tips to Avoid Epoxy Grout Sealant Problems

To ensure a perfect application and a perfect bond with the tiles, there are some factors mentioned below that would help you avoid the problems discussed above.

1. The 40cm Rule: This rule tells the users to discard the first 40cm of epoxy grout in the cartridge, as it can contain air particles and may carry inconsistencies in mixing.

2. Temperature Matters: For applying grout, the ideal working temperature is 15°C to 30°C. If the temperature is too low, the grout can get thick, so heat the grout, and if it's too hot, work quickly as the grout at high temperature hardens a lot quicker.

3. Keep it Dry: Consider moisture as an enemy of epoxy grout. It prevents the epoxy from curing and bonding. After application, keep the area dry for at least 24 hours.

4. Change the Nozzle: Once you have stopped working for 15 to 20 minutes, the grout inside the mixing nozzle will harden. It's better to replace the nozzle with a new one instead of forcing the old one to work.

4. KASTAR Dual-Pipe Epoxy Grout Sealant Reduces Mistakes

Most of the problems listed above can be avoided by using a proper technique and choosing KASTAR Dual-Pipe Epoxy Grout Sealant. What makes KASTAR Dual-Pipe Epoxy Grout such a great option is its ease of use and the quality of materials used.

• High-Solid Formula: KASTAR has been using a high-solid content formula, which eliminates the problems of shrinkage once cured. This makes their dual-pipe epoxy perfect for preventing cracks from forming due to volume loss.  

• Stable Pigments: KASTAR offers epoxy grout with multiple types of finishes to match the overall aesthetics of the space. To ensure that these finishes last, KASTAR has been using cosmetic-grade pigments that are highly resistant to fading from UV rays compared to standard industrial grades.

• Smooth Flow: The dual-pipe design ensures that uniformity is maintained for effective application. Furthermore, KASTAR ensures an optimal consistency to ensure smooth flow and helps to prevent problems like hand-fatigue and ripple effect.

By using KASTAR, you are starting your project with a material designed to resist peeling, cracking, and discoloration, giving you a professional result that lasts for a lifetime.

5. Conclusion

Using a two-tube epoxy grout sealant is the best way to achieve a waterproof, beautiful finish for your home. While issues like bubbles or peeling can be intimidating, they are almost always caused by moisture, dust, or simple application errors. Do ensure that the surface is prepped correctly by making sure it is a clean and dry surface that is free from moisture, dust, greasing, and old wax, so that epoxy grout can be perfectly bonded with the tiles. Make sure when choosing an epoxy sealant, select a premium product like KASTAR to ensure the durability and surface finish that lasts longer.

6. FAQs

Q1. Can I apply epoxy grout sealant over old grout?

It's not preferred to apply the epoxy tile grout directly over the old grout. For effective bonding, a minimum space of 3mm is required to bond the sides of the tiles. With the old grout still in place, this clearance space wouldn't be possible.

Q2. How to Remove Dried Epoxy Grout from Tiles?

After applying, if excess grout is left out and has dried up, instead of chipping or hammering, use a heat gun or hair dryer to soften it and then remove it using a plastic scraper or blade. Wipe any residue with alcohol.

Q3. Why does my epoxy sealant feel sticky after it has cured?

It is most likely due to uneven mixing. The resin and hardener should be in a 1:1 ratio to prevent such problems. It's better to scrape it out, ensure the gap is clean, and reapply the fresh grout by removing the first 40cm of the tube and avoiding using an old mixing nozzle.