How to Seal Grout 

 August 9, 2021

By  Dale Keese

Often, you may be left wondering why despite spending a lot of time and effort to clean the tiles in your bathroom, your bathroom still looks dirty and dull. The culprit is dirty and grimy grout lines, which can diminish the look of your tiled walls and floors.

Blue and White Bathroom Interiors

Grout is a mixture of cement, water, and sand. By nature, grout is porous and tends to absorb various substances such as water, oil, and grease, which makes grout very dirty and discolored. The best method to keep the grout clean and prevent your bathroom from looking dirty is to do some grout sealing. A grout sealant keeps mold and mildew away by sealing the newly laid grout and resealing it whenever required.

Since the floor and wall tiles do not get a lot of moisture, it is recommended that you seal the grout once a year or as needed. For your bathroom backsplash and shower, you need to do grout sealing more often.

Sealing grout when it is freshly laid with a high-quality grout sealer will help prevent dirt and grime from working their way into the grout lines. Although your grout may contain additives to prevent mold and mildew, a grout sealant offers added protection.

Sealing the grout can help extend the lifespan of your grout. If you actually understand how to seal grout, then you will find that it is an extremely easy and quick job that you can do on your own. Some of the advantages of sealing grout are.

Reduces Staining

Sealing the grout can help prevent and reduce the effect of grout staining. Now, with the help of a grout sealer, there is no need for you to spend hours of your time and effort bleaching away the stains because there is a seal to protect it.

Reduces Moisture

Applying a grout sealer to the grout can help prevent moisture from penetrating the tiled surface. Grout sealing is especially important for bathrooms and kitchens because they are always in contact with water, humidity, and steam.

By following the steps below, you can learn how to seal grout and prevent the dull, stained appearance of your tiles.

Mosaic Tile Design

How to Seal Grout: Steps

Step 1: Cleaning and Repairing the Grout

Before applying the grout sealant to the grout, you must ensure that the grout is cleaned properly. Any crumbles and cracks in the grout lines should be repaired; otherwise, all the dirt and the damaged joints will be sealed in when you apply the grout sealer. Take some warm, soapy water and using a toothbrush, try and remove the grime and dirt off the grout as much as you can.

If the grout is stained, then you can use a mixture of 1-part vinegar mixed with 1-part water. Clean the grout lines one at a time and once you have finished cleaning, let the entire area dry for at least 30–40 minutes before you begin the grout sealing process.

Step 2: Choosing the Sealer

Next, you must choose the appropriate type of grout sealer depending on the kind of tile you have and its location. There is no one-size-fits-all approach to choosing the best grout sealer and there is no single grout sealer that is ideal for all kinds of situations. You can find a variety of grout sealers that you can customize according to your requirements to a certain extent.

Certain grout sealers are best for tiles made of stone, ceramic, and marble. The amount of moisture that can be tolerated by the grout sealer also matters whether you need sealing for an area with low moisture such as your kitchen backsplash or a high-moisture area such as the bathroom shower. You can select the appropriate grout sealer depending on the type of tile and its location.

There are essentially two main categories of grout sealers that you can use to seal grout: membrane-forming grout sealers and penetrating grout sealers.

Membrane-Forming Sealers

This type of grout sealer works by creating a coating on the surface of the grout, which prevents water from infiltrating the seal. This is more suitable when sealing grout in the kitchen. It is not recommended to use membrane-forming grout sealers in your bathroom because this type of grout sealer do not allow the water trapped below the tile to evaporate and in a shower, this can lead to the growth of mold and mildew in the grout.

The membrane-forming grout sealers also contain pigments that can change the color of the grout after sealing. While this type of grout sealers are suitable to seal unglazed tiles such as stones, they are not recommended to seal glazed tiles like ceramics.

Penetrating Sealers

This type of grout sealer uses either a water base or a mineral spirit base to seal, which allows the minute particles of silicone or latex in the formula to penetrate the grainy structure of the grout. Since the grout is porous, the grout absorbs the silicone or latex particles, which fill the gaps after grout sealing. This helps to keep the moisture out.

Penetrating grout sealers are best for sealing damp areas like bathrooms, particularly in the shower area.

Spacious Kitchen

Step 3: Choosing the Sealer Applicator

You need the right kind of grout sealer applicator to seal the grout successfully. While aerosol grout sealers that can be sprayed on are the most popular because of their convenience and ease of use, in most cases, these spray-on grout sealers may not be suitable for the project.

  • If the grout lines are very thin and the tiles are unsealed, then you can make use of a sponge, which lets you seal larger segments of the bathroom floors and walls by wiping both the grout and tile surfaces all at once
  • If the tiles are glazed and you are having a problem with the grout sealer not adhering, then you will have to seal only the grout lines by using an applicator brush or an applicator bottle that has a rolling wheel on the top. The roller wheel applicator is ideal to seal wider grout lines on flat surfaces such as tile floors.
  • The brush-tipped applicator is suitable for sealing vertical grout lines and joints in backsplashes and showers and can also be used to seal small grout joints.
  • No matter what grout sealer applicator tool you decide to use, do read the manufacturer’s instructions on how to seal the grout properly before you start.

Step 4: Applying the Sealer

Apply the grout sealer carefully and seal small sections at a time. Start from the left and move to your right. Working methodically as you seal will help your grout lines look neater and more consistent. This way, you will not overlook any areas and the grout sealer will offer better protection. Keep a dry cloth at hand and use it to wipe off any excess grout sealer.

Avoid dripping the grout sealer on glazed tiles, whether you are using an applicator or sponging a large area. If any grout sealer drips onto the tile, make sure to remove it immediately before the grout sealer begins to dry. Leaving it for a longer time will leave a foggy layer over the tile, which will be impossible to remove later on when the seal is dry.

Step 5: Applying the Second Coat

Once you have applied the first coat of grout sealer, let it dry for at least an hour before applying the second coat. It is recommended that you apply at least three coats of the grout sealer in order to seal it well and get sufficient protection. Once the second coat dries, use a few drops of water to test the surface. The water should bead up into drops if the seal is effective. If this does not happen, then apply another coat of the grout sealer to ensure that you get the best results.

Once all the steps are completed, let the tiled area dry fully. While some grout sealers may require 24 hours for curing, others may take around 48 hours to seal. To be sure, check the manufacturer’s instructions on how to seal grout.

Installing Tiles

How to Seal Grout: Some Dos and Don’ts


Here are a few tips that you should follow while sealing the grout for best results:

  • You must seal only cement-based grout. There is no need to seal synthetic grouts such as urethane and epoxy because sealing synthetic grout may do more harm than good in protecting the grout. Also, grout that has been dyed, re-colored, or sealed using an epoxy-based grout colorant must not be sealed. Grout colorants already adds a layer of sealer on the grout and so sealing the grout again can be more harmful to the grout.
  • If your grout has been deep cleaned, then ensure that you seal the grout again because deep cleaning the grout using strong acidic or alkaline cleaners can cause the sealer in the grout to break down. Also, over time, grout cleaners break down, so you must seal the grout once every 3 to 5 years.
  • Maintain the grout and clean it regularly with mild soap and water. Avoid using harsh detergents or chemicals after you seal the grout as they can reduce the benefits of sealing.
Bathroom and Sink


It is extremely important to know how to seal grout and here are mistakes that you should avoid:

  • Avoid sealing damp grout or your job can turn into a complete mess. Sealing the grout before it is completely dry and hard is a big mistake and will make the seal useless. While you may be able to apply the grout sealer while damp, the grout sealer will start flaking or peeling off, leaving your grout prone to stains and dirt.
  • Sealers dry very quickly—whether on the grout or the tile. It is quite difficult to seal the tile without the grout sealer getting onto a small part of the tile. If, while sealing the grout, some of the grout sealer gets onto the tile and it is not removed immediately, the grout sealer will dry on the tile surface and you can see spots on the tile that will spoil its beauty and shine. While some grout sealers may take a longer time to dry compared to others, it is always safe to clean away any extra grout sealer that may have been applied on the tile by mistake with a soft cloth.
  • Spray-on grout sealants can be quite convenient and quick to use because it can be directly sprayed on the grout. However, this has its drawbacks too. If you try spraying the grout sealer while you are standing, the spraying will not be as accurate as when you are closer to the grout. You will most likely spray some grout sealer on the tile surface and then you will have to spend unnecessary time and effort in cleaning the grout sealer off the tile. Also, you may miss covering all the grout with the sealant.
  • If you apply the grout sealer carefully and methodically, the grout and the tiles will look neater and more uniform. The seal will protect your grout, as well as the tile, from moisture and stains effectively. Avoid applying the grout sealer randomly; start at the far corner of the room and then work your way across the tiles. If you do not do this, you may find that you missed out on some areas or that you only covered an area partially and the seal can dry out before you get to cover the whole area completely.
  • While it is quite easy to get extra grout sealer on the portions of the tile that must not be covered, you may find cleaning off the excess grout sealer a hassle. However, do not give up. If you buff the tile vigorously with a cloth, the grout sealer can be removed easily.

Blue Kettle on Kitchen Counter

Grout is very porous and can attract dirt, grime, bacteria, mold, and mildew. Sealing the grout can help protect it from all these contaminants and the seal will also prevent it from getting dirty and stained. While you may find it a hassle to keep the room where you are sealing the grout off-limits for a couple of days, you will realize that it is completely worth it when you clean the grout next time.

Using a good sealer and sealing the grout well translates to lesser time spent scrubbing the grout clean. So, in short, by sealing the grout, you can make your tile and grout cleaning routine a piece of cake.

LA Times

About the author

Hey, I'm Dale Keese.. thanks for reading.. hopefully this article can save you some time and trouble with your sealing job. I'm also in the process of making some video walk-throughs for youtube so check back soon! thanks

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