What Causes Grout To Crack In The Shower? (Find Out Now!)

Ossiana Tepfenhart
by Ossiana Tepfenhart

Grout is one of those things that is meant to look perennially crisp and clean. Unfortunately, when reality hits, it’s often a different story. Usually, this can all be fixed with a little bit of bleach and scrubbing. Dirtiness aside, the biggest issue grout can have is a crack. Cracks are rare with grout, primarily because it’s not supposed to happen. When they do, you might be wondering what caused that grout crack.

In most cases, new grout that cracks is a result of improper mixing—often too much water, leaving air pockets that weaken the grout structure. Not using enough adhesive when applying the grout can also cause the grout to disconnect and crack. Though rare, impacts from heavy objects can cause cracks in both grout and tiling nearby.

Seeing a grout crack is a clear sign that it may be time to take a trip to the hardware store. It’s not just an eyesore. It’s a sign that your walls could be exposed to moisture, which in turn could cause serious issues. Let’s talk about what makes this happen and how you can avoid it.

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Why Is My Shower Grout Cracking?

There are several reasons why shower grout could crack, and all of them are things to be wary of. Most of the time, the grout’s cracks have to do with bad mixing or building. Here’s what to be aware of as far as potential build cracks go…

Too Much Water

Most grout cracks have their beginnings right at the moment where the grout is mixed. People have a tendency of adding too much water to grout. The big issue that this causes is that thin grout is runny, weak grout. This makes it more fragile by default. However, it’s not just the watery build that makes it bad. It’s also the air pockets.

Lots of water means that you will likely deal with air pockets bubbling up. This turns your grout into Swiss cheese on the inside. When air heats up, it expands. That makes the thin shells of the air pockets crack and shatter over time. If you notice a lot of flakiness on your grout, this is why. Regrouting your shower might be the only way to fix it.

Note: Exposure to excess water can also cause grout cracking by way of mold growth.

Low/Bad Adhesive

A shower can’t be built on grout alone. In order to to get your grout to stay in place, you need to have the right adhesive applied on in the right amounts. If your adhesive isn’t well-applied, your grout will start to crack over time. It’s not being held in place well! To avoid this, make sure that you get the suggested type of grout adhesive that your shower grout needs—if it needs any.

If you notice that your tiles have been loosening up a bit, chances are that your adhesive wasn’t mixed or applied well. Regrouting your shower is the only way to make sure this gets fixed. Sadly, that also means you may need to choose a different adhesive.

Too Many Movements

Every time that temperature changes, your grout will expand. The same can be said, to a point, about moments where too much moisture ends up near grout. When grout dries or gets cold, the grout (and everything around it) will shrink. These movements are extremely small and happen on microscopic levels.

Once in a while, having this happen isn’t that big a problem. However, if it happens enough times, it will eventually cause your tile grout to crack and chip. All those little movements add up over time. For the most part, choosing a flexible grout type is the only way to partially prevent this. Even then, you should understand that it’s an eventuality.

Water Under The Tile

Oof. This is a bad sign. Did you decide to grout up the shower area when it was wet? Or worse, did you notice that there was a hole in your grout? When water hits grout from the base of the tile, cracks are going to form. Keep an eye out for wet grout when the shower area is mostly dry. This means that you have water under the tile.

Sadly, this usually is a reason to give your entire show area a full re-grouting. There’s no shortcut here. Ignoring this can cause serious damage to your home’s walls and even cause black mold to happen. Due to the severity of the fallout from this kind of issue, you need to treat this problem as soon as you see it. It’s a legit emergency.

Impacts

This is the final reason why you might see that grout can crack, but it’s the most obvious one by far. If you drop a bowling ball (or any other item similar to that) on grout, the grout will crack. This is because grout can only take so much pressure before it cracks. Thankfully, this means that you can usually patch up the damage and not worry about further problems down the line.

How Do You Treat Cracked Grout?

Regardless of the cause, the solution for cracking grout is still the same. To fix cracked grout, you only really have one choice: you need to re-grout the damaged area. In some cases, you can get by with patching the cracked area. Apply a little extra epoxy grout is more than enough to make most cracks go away.

However, some areas are going to need a lot more than just a patch. If you realized that your grout is showing cracks throughout the shower area, you probably did a bad install or have grout that’s ancient. This means that you will need to re-grout your entire shower area in order to prevent cracks from happening. (Might we suggest going with a professional this time around?)

Does All Grout Eventually Crack?

Here’s the thing that you need to be aware of: all grout will eventually need replacement. Sometimes, it could be in as little as five years. Other times, the grout will only crack after decades of being steady and stable. Regardless, all grout will eventually need a patch or replacement. This is not a reflection on you in most cases. It’s just the way that building maintenance is.

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Related Questions

Can you put new grout on top of old grout?

This is a pretty bad idea in most cases. The best thing you can do is to remove the grout that has cracked in your shower, then add new grout and adhesive to the offending area. Small patches of grout to make the area seamless are also totally cool. With that said, you need to make sure that you remove all the grout that needs to be replaced. Otherwise, you are going to have a bad time with your grout maintenance.


Can black mold also cause cracks in grout?

When mold takes hold, it doesn’t just chill out on top of grout. The tiny tendrils that are a part of mold’s structure will sink into tiny pores in the grout. As the mold grows and spreads, this will weaken the grout. This is why most grout that has a serious mold infestation needs to be fully replaced. It’s just too weak to stand on its own. This is just one of many reasons why you need to kill black mold ASAP.


How long should you expect grout to last?

While there are always cases where grout just seems to last forever, the truth is that most grout will be able to last anywhere from eight to 20 years with proper care. High-quality grouting in ideal environments should last a minimum of 15 years. It’s not unheard of for grout in areas like this to last as long as 25 years if you are persnickety about using gentle cleaners.

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Ossiana Tepfenhart
Ossiana Tepfenhart

Ossiana Tepfenhart is an expert writer, focusing on interior design and general home tips. Writing is her life, and it's what she does best. Her interests include art and real estate investments.

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