11 Myths About Sealing Grout & Tiles (Avoid These!)


Sealant for tiles and grout is touted as a must-have for many households. Whether that’s to protect your natural stone tiles or your grout doesn’t matter.

Many of us are told things about grout and installing new tile that will impact decision-making during the installation. 

However, often, we’re told myths. And, in some cases, those myths can be actively harmful. The following includes 11 common myths about sealing grout and tiles. 

1. It’s Always Necessary To Seal Grout

Sealing grout can add a lot of value. In some cases, it may even be necessary. In other instances, it can be actively harmful and can cause damage to the rest of your home. 

Why? Grout and porous tile absorb water. That’s why grout sealant is sold to prevent mold and mildew growth. While it’s true that grout sealant will prevent issues in the short term, it can cause them in the long term. 

For example, when older grout starts to crack, water can get underneath. That will cause water buildup, which can result in rot and mildew under your tiles. 

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Even in a bathroom, where grout is frequently exposed to water, sealing grout may be a bad idea. For example, if you take hot showers and steam heats the tile, it will condensate behind it. If the grout is sealed, the water will have no way to escape. 

Sealing grout can be a good idea. And, it can help you to prolong the life of tile or to protect wood substructures underneath.

However, it isn’t always necessary. You should always discuss whether or not you have to seal grout with your builder before taking steps to seal the grout. 

In many cases, you’re actually better off not sealing grout. If you do, make sure you choose a type of grout sealer that works for your grout and doesn’t permanently trap moisture. 

2. You’re Better Off Sealing Grout Than Tiles 

If you’re using natural stone tiles like limestone, marble, or slate, you’ll always have to seal the tiles. Otherwise, they will absorb a significant amount of water. Absorbing water could also cause those tiles to expand and crack. 

Therefore, porous tiles should always be sealed before you apply the grout, prior to installation. In addition, you should wait until the grout is fully cured, and then seal the tile again.

You’ll also want to periodically check and re-seal the tiles to ensure they stay in good shape. 

In fact, if you don’t seal the tile before you install the grout, the tile will absorb the grout. That will ruin the finish. And, you’ll never be able to get the grout out of the tile. 

So, while sealing grout is optional, you’ll almost always want to seal the tile. That is, unless you have porcelain or ceramic tiles with a glazed finish. As these aren’t porous, you won’t have to seal them.

In addition, you should always check if your porcelain tiles are glazed or not. If not, they may have to be sealed as well. 

3. Grout Is Permanent 

Most people believe that once grout goes in, it’s in forever. Unfortunately, that isn’t true. Grout eventually starts to crack.

Depending on the conditions in your bathroom or kitchen, grout will last anywhere between 8 and 20 years. 

Here, you can prolong the lifespan of your grout with good maintenance. That will mean: 

  • Maintaining regular temperature in the room, with no sudden hot or cold fluctuations
  • Cleaning up moisture and spills quickly 
  • Preventing moisture from being trapped under the grout, where temperature changes could cause it to expand, forcing the grout to crack 
  • Cleaning using non-abrasive substances (E.g., no harsh chemicals and no wire brushes)
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You’ll always have to replace the grout eventually.

But, keeping it clean, avoiding using abrasives, and avoiding using chemicals that break down the grout will ensure that your grout stays like-new for longer. That includes with or without a sealant. 

4. Grout Sealant Is Permanent 

Photo: MTA Construction & Development Mega Projects / Flickr / CC BY 2.0

Most people think that if they apply grout sealant, it’s done. Unfortunately, grout sealant normally only lasts for about a year.

Afterwards, you’ll have to remove or clean the old sealant and apply a new one. However, some forms of grout sealant can last significantly longer. 

However, in almost every case, your grout sealant should be checked and replaced on a yearly or twice-yearly basis. That’s especially true if you have a non-membrane sealant.

Waxes and polishes might wear off every time you mop and clean the floor with chemical cleaners. This means you might have to keep re-applying them. 

However, that’s even true if you use membrane-based sealants like caulk. If you clean them with a harsh chemical cleaner, they will deteriorate.

With caulk, that could mean coming loose around the edges. This effectively less water and moisture under the seal, right where you don’t want it to be. 

That will mean effectively having to use a chemical cleaner or peeling grout sealant on a yearly basis. You’ll then have to re-apply it to maintain the effect.

This means that once you start sealing grout, you’re committing to ongoing work just to maintain it. 

Here, some forms of grout sealant can last longer. For example, resin and acrylic grout don’t have to be sealed. This means they also don’t require ongoing maintenance and replacement. 

5. Sealed Grout Can’t Get Dirty

It’s normal to see statements like “Sealing grout is an alternative to mopping”. Unfortunately, this couldn’t be further from the truth.

Sealed grout still gets dirty. In fact, it can often harbor more bacteria and spores than grout can. 

Why? Water pools on the surface of the sealant instead of being absorbed. This means that, until you mop or clean it up, water will sit there.

That will be more prone to allowing slime and other molds to proliferate. 

Therefore, sealed grout needs just as much cleaning as unsealed grout. In some cases, it may actually need a bit more attention.

However, it is less likely to show dirt and it will look cleaner after you clean it. For example, if you have unsealed grout, dirt can get into the porous material. When you clean over it, you only clean up the surface. 

So, putting sealant on your grout is very unlikely to help with keeping your floors clean. However, it might make them look cleaner after you clean them.

At the same time, you’ll still have to wipe water and spills up quickly to prevent staining, bacteria, and mold. 

6. You Can’t Seal Old Grout 

It’s a common belief that you have to seal grout immediately or you can’t seal it at all. This isn’t true. In fact, you can seal grout at any point, even if it’s several years old. 

Here, the myth comes from the fact that you normally want to apply sealant quickly to maintain the appearance of the grout. For example, if you have a sheer or clear grout sealer, the original grout will show through.

In this case, you’ll want to apply the sealant as quickly as possible after laying the ground. Normally, that’s about 48 hours after putting the grout in. 

However, there’s nothing stopping you from applying sealant later. However, if you’re applying the sealant on old or stained grout, you may want to cover it up.

In this case, a membrane-based sealer that changes the color of the grout may be a good idea. This will completely cover the grout and you won’t see it. Therefore, it won’t matter if it is stained. 

At the same time, if your old grout is moldy or mildewing, it’s a good idea to bleach it first to ensure that those mold spores are dead. Otherwise, you’ll just be covering up a problem. 

7. All Sealants Are The Same 

There are multiple different kinds of grout sealer. Most of them do slightly different things and are suited for different types of usage.

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For example, the best grout sealers are a type of wax, which add waterproofing and splash resistance. However, they don’t fully “seal” the grout, meaning that it can still breathe. 

Other grout sealers fully cover the grout with a membrane. These close off air to the grout and any moisture trapped underneath will remain there forever. However, if your grout is old or damaged or you live in a dry area, it can be a great choice. 

Penetrating Sealer – Penetrating grout sealers are made up of wax, oil, and polymers or phenols. These penetrate the porous surface of the grout and impregnate it. Then, when you spill water or splash grease on your floor, the grout doesn’t absorb it. 

These types of sealants are ideal for kitchens, especially backsplashes, because they prevent your grout from absorbing fat and grease from the kitchen.

However, on floors, they very often erode away quickly. This might mean you’ll have to apply them twice a year instead of once a year. 

However, penetrating sealers can also offer great water resistance. Many are designed to simply prevent water from soaking into the grout.

Because they’re lighter than caulk or other membrane sealers, they’re also easier to clean off and re-do when it becomes necessary. 

Membrane Sealers – Membrane sealers include substances like caulk and latex-based sealers. These fully cover the grout and usually penetrate into the porous material. Here, they work to waterproof the grout by simply covering any open holes. 

Normally, membrane sealers also significantly change the look and feel of the grout. For example, you can buy them in tinted colors or in white. In either case, you’ll no longer be able to see the original color of the grout. 

Membrane sealers also don’t allow grout to breathe. This means that if water is trapped underneath, it can cause issues. 

In addition, membrane sealers are prone to peeling around the edges. Once this starts, the only way to fix it is to peel everything up and re-lay it.

However, you likely won’t have to replace it until those issues start happening. And, that can take 1-3 years depending on how much your bathroom is trafficked. 

However, both caulk and latex-based sealers are prone to black mold. This means you’ll still have to clean them as spills happen. That’s especially true if you live in a damp area or if your bathroom has poor or no ventilation. 

8. Sealed Grout Doesn’t Need Maintenance 

Photo: Lisa Boska / Flickr / CC BY NC 2.0

Most people install grout sealer to avoid having to put maintenance on the grout. However, you’ll still have to maintain the sealer. 

In fact, most grout sealers require as much or more maintenance than the grout itself. For example, if you have a penetrative sealant, you’ll have to redo it at least once a year and sometimes more often. 

If you have a membrane sealer, you’ll likely have to redo it every year. However, if it’s on a wall or in another area where you don’t walk or touch, it might last several years longer. 

In either case, you’ll also have to maintain keeping the area clean. Dirt, fat, and moisture buildup will still cause the sealer to degrade. And, after it degrades, the grout will be left unprotected. 

In addition, cleaning and replacing grout sealer can damage your grout. If you have to scrub off an old resin sealant, you could damage the grout underneath. That could result in hours of extra work repairing the grout. 

9. One Coat Of Sealant Is Enough 

One of the most common DIY mistakes when installing grout is to apply a single, thick layer of grout sealer. However, that never works. Grout sealer must always be applied in two coats. 

Here, the first coat works its way into the grout. That’s important for ensuring that sealant actually stops water and other liquids from doing the same.

However, after that first coat, the top grains of the grout will still be exposed. 

Therefore, you’ll have to apply a second coat. Normally, that means waiting 1-48 hours (depending on what type of grout sealer you’re using) and then applying a second coat. In each case, the coat should be thin. 

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In some cases, if you apply a spray-on sealant, you might need more than two coats. However, that will only happen if you apply the sealer too thin. 

10. Grout Sealant Doesn’t Stain 

Many people opt for grout sealant because it doesn’t stain. Unfortunately, that is a myth. Grout sealant will stain and discolor, just like grout. However, it will be easier to clean off. 

For example, latex and caulk are some of the most common materials for sealing grout. Both can stain if you drop food on them.

In each case, they can also discolor because of dirt. And, both are prone to black mold, which can be difficult to fully get rid of without bleach – which can damage the sealer. 

Here, you can take steps to reduce staining by choosing a darker grout sealer. That won’t eliminate the dirt. However, it will make dirt and stains less visible.

You can take this route even if you’re using a penetrative sealant. For example, many brands sell tinted sealants, which allow you to darken the grout.

If you use that, you’ll have to pay more attention when the grout is dirty. That’s because you won’t be able to see it as much. But, it will still be just as important to keep it clean. 

11. You Can’t Seal Grout Yourself 

Many people think you have to hire a professional to seal the grout. That’s almost never true.

However, if you want to spray on grout, hiring a professional is almost always a good idea. That’s because buying or renting a sprayer and learning to use it with finesse will be time and labor-intensive.

In addition, you’re very likely to have to clean sealant off tiles while you learn to use the sprayer properly. 

You should never apply a sealant to grout that is not fully cured. This can take 48-72 hours depending on your grout. 

Instead, most DIY jobs are done using a brush or applicator. Here, the tools used depend on the type of grout. However, you can always use the following steps: 

  • Clean the grout or allow it to fully cure if it is new. 
  • If there are signs of mold or mildew, bleach the grout before getting started.
  • Tape off any areas you don’t want to stain, e.g., baseboards, tubs, etc. Some grout sealants can stain and it will be difficult to get off.
  • Use a foam sponge or roller to apply the grout sealant to the lines. In some cases a grout groover or a trowel will do the job as well, however, you’ll always want a sponge to go over the work with you. 
  • Push the grout sealant into the lines, being sure to cover them thoroughly, Do a full line, and then clean the sealant off the tiles. In most cases, you should let the sealant sit for about ten minutes before cleaning it off of tiles. 
  • Allow the grout sealer to dry or cure according to instructions (usually 1-24 hours) and then apply the second coat. 
  • Clean up any mistakes or messes as quickly as possible. If you miss any, steel wool or a stiff brush (spot-check this on an unused tile or in a corner) will get the rest of the sealant up. 

In most cases, you can expect applying grout sealant to take several hours of your time.

In some, the full process can take over a week depending on how long your layers have to cure. 


Applying grout sealant is something almost anyone can do. However, the following tips should help you get it right: 

  • Use a penetrative sealer that you can remove and reapply cleanly for most applications.
  • Caulk and latex sealants are ideal for use on bathroom walls but will peel when walked on frequently. So, if you want to waterproof your bathroom walls, use a penetrative sealant. 
  • Look for grease-resistant sealants for kitchen usage.
  • Always clean grout before applying sealant.
  • Wipe up spills and excess grout sealer after about 10 minutes.
  • Always check the instructions before applying a second coat of sealant. Some products require that you wait several days before applying the next one.