How to Seal Grout

  • July 26, 2019
  • / By Dale Keese
Blue and White Bathroom Interiors

Often, you may be left wondering that 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 take away from the look of your tiled walls and floors. 

Blue and White Bathroom Interiors

Grout is a mixture of cement, water, and sand; and by nature, it is porous and tends to absorb various substances such as water, oil, grease, etc. which make it very dirty and discolored. The best method to keep the grout clean and prevent your bathroom from looking dirty and also keeping mold and mildew away is 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 so but it is better to reseal the grout on your bathroom backsplash and shower more often.

Sealing grout when it is freshly laid with a high-quality grout sealer will help to prevent dirt and grime from working their way into the grout lines. And, although your grout may contain additives to prevent mold and mildew, a sealer offers added protection against mold and mildew growth. Also, sealing the grout can help to extend its life and if you actually understand how to seal grout, then 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 to prevent and also reduce the effect of staining. Now, there is no need for you to spend hours of your time and effort bleaching away the stains.

Reduces Moisture

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

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

Mosaic Tile Design

How to Seal Grout: Steps

Step 1: Cleaning and Repairing the Grout

Before applying the sealer 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 get sealed in. Take some warm soapy water and using a toothbrush, try and remove as much of grime and dirt as possible. If the grout is stained, then you could 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 sealing process.   

Step 2: Choosing the Sealer

Next, you must choose the appropriate type of sealer on the basis of the kind of tile and the location. There is no one-size-fits-all approach to choosing the sealer and there is no single 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 sealers are best for tiles made of stone, ceramic and marble and also the amount of moisture that can be tolerated by the sealer, whether you need it for an area with low moisture i.e. along your kitchen backsplash or a high-moisture area such as the bathroom shower. You can select the appropriate sealer depending on the type of tile and the location. There are essentially two main categories of sealers i.e. membrane-forming and penetrating sealers.

Membrane-Forming Sealers

These work by creating a coating on the surface of the grout which prevents water from infiltrating it. These types of sealers are suitable for use in the kitchen; however, it is not recommended that you use membrane-forming sealers in your bathroom because these sealers 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. The membrane-forming sealers also contain pigments that change the color of the grout. While these types of sealers are suitable for unglazed tiles such as stones, they will not adhere to glazed tiles like ceramics.

Penetrating Sealers

These sealers use either a water base or a base of mineral spirit 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, it absorbs the silicone or latex particles, which fill the gaps and this helps to keep the moisture out. Penetrating sealers are best for damp areas like bathrooms, particularly in the shower areas.

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Step 3: Choosing the Sealer Applicator

You need the right kind of grout sealer applicator. While aerosol sealers that can be sprayed on are the most popular because of the convenience and ease of use, in many cases these spray-on 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 sealer not adhering, then you will have to seal only the grout lines by making use of 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 also for small grout joints.  

However, whichever applicator tool you decide to use, do read the manufacturer’s instructions on how to seal grout before you start.

Step 4: Applying the Sealer

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

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

Step 5: Applying the Second Coat

Once you have applied the first coat of sealer, let it dry at least for one hour before applying the second coat. It is recommended that you apply at least 3 coats of the sealer in order to 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 and if this does not happen, then apply another coat of the sealer to ensure that you get the best results.

Once all the applications are completed, let the tiled area dry fully. While some sealers may require 24 hours for curing, others may take around 48 hours. To be sure, check your 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, epoxy, etc., because sealing synthetic grout may do more harm than good in protecting them. Also, grout that has been dyed, re-colored or which has been sealed using an epoxy-based grout colorant must not be sealed. Grout colorants add a layer of sealer on the grout that also seals the grout and so sealing the grout which has a colorant applied can be more harmful to the grout.
  • If your grout has been deep cleaned, then ensure that you reseal it because deep cleaning the grout using strong acidic or alkaline cleaners can cause the sealers 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, as they can cause the benefit of the sealing to be reduced.
Bathroom and Sink


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

  • Avoid sealing the grout that is damp before it dries completely 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 not be effective. While you may be able to apply the sealer, the sealer will start flaking or peeling off leaving your grout prone to staining and becoming dirty.
  • Sealers dry very quickly, whether on the grout or the tile. It is quite difficult to seal the tile without the sealer getting onto a small part of the tile. If while sealing the grout, some of the sealer gets onto the tile and it is not removed immediately, the sealer will dry on the tile surface and you can see spots on the tile that will spoil its beauty and shine. While some sealers may take a longer time to dry when compared to others, it is always safe to clean away any extra sealer that may have been applied on the tile by mistake with a soft cloth.
  • Spray-on 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 sealer while you’re standing, the spraying will not be as accurate as if you were closer to the grout. You will most likely spray some sealer on the tile surface and then will have to spend unnecessary time and effort in cleaning the sealer off the tile. Also, you may miss covering all the grout with the sealant.
  • If you apply the sealer carefully and methodically, the grout and the tiles will look neater and more uniform and the sealer will protect your grout, as well as the tile, from moisture and stains effectively. Avoid applying the sealer randomly and start at the corner of the room and then work your way across the tiles. If you don’t do this, you may find that some areas have been missed out or only covered partially and can dry out before you cover them completely.
  • While it is quite easy to get extra sealer on the portions of the tile that must not be covered, you may find cleaning off the excess sealer a hassle. However, do not give up. Although the sealant may seem to be difficult to remove from the areas if you buff the tile vigorously with a cloth, the sealer can be removed easily.
Blue Kettle on Kitchen Counter

Grout is very porous and can attract dirt, grime, bacteria, mold and mildew and sealing the grout can help to protect it from all these contaminants and also prevent it from getting dirty and stained. While you may find keeping 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 the next time.

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