What is Grout Sealant?

Mary McMahon
Mary McMahon

Grout sealant, also known as grout sealer, is a product which is designed to be applied to tile grout to protect it from hard use and the elements. This product is available from many hardware stores. Applying sealant is an important step in the grouting process which serves a number of functions. For people who have hired a contractor to install and/or grout tile, it is important to ask whether or not sealer was used.

Floors with heavy traffic or high exposure to moisture need more frequent re-sealing.
Floors with heavy traffic or high exposure to moisture need more frequent re-sealing.

Most grouts are porous. This means that they will absorb water, and over time, this can damage the substrate of the grout in addition to eroding the grout itself. Mildew and mold will tend to develop, and they will spread under the tile, leading to serious problems in the future. In addition, the porous nature of grout makes it a magnet for dirt and stains, and it will quickly become unsightly with use.

Grout must be cleaned before applying sealant.
Grout must be cleaned before applying sealant.

Grout sealant resolves both of these problems, protecting the grout and the underlayer from stains and the elements. Some sealants form a membrane over the grout, while others penetrate the grout. In both cases, when a grout sealant has been applied and it is working as it should, a drop of water on the grout should bead up, rather than sinking into the grout. Since tiles are often already sealed, the grout sealant ensures that a tiled area stays watertight. If the tiles also need sealing, a general sealant will need to be applied to the whole area.

Some grout sealants come in the form of a spray, while others are brush on. It is important that the grout be dry when sealant is applied, as otherwise, moisture will be sealed into the grout. If grout is freshly laid, people should wait two to three days before putting down sealant, remembering that the core of the grout can be damp when the outside seems dry. After the sealant has been applied and allowed to cure, it can be checked by sprinkling water on the grout to confirm that it beads.

With use, grout sealant wears down. On a high traffic floor, it may be necessary to reseal every six months or so, while other areas may stay well sealed for up to two years. When resealing, people should scrub the grout and allow it to dry fully before applying a new layer of grout sealant. Whenever new grout is laid, sealant should be the final step.

For people who do not want to have an added complication when it comes to grouting, epoxy grout can be used. Epoxy grout needs no sealant.

Applying a sealant after grout is dried will help waterproof the areas between tiles.
Applying a sealant after grout is dried will help waterproof the areas between tiles.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


I would love to know more about the epoxy grout if anyone has used it. Grout that needs no sealing sounds perfect but I wonder if it really stays clean and if there are any negatives to using it.


@otatop, there are a number of ways to clean grout prior to sealing that won’t affect the sealant. You can use a mixture of baking soda and water, made into a thick paste, then brushed with a toothbrush over the grout. This works really well.

Just make sure you rinse it all off when you’re done so that there isn’t any residue left. If there are grease stains, use a kitchen degreaser and let it sit for about ten minutes before scrubbing and rinsing.

I’ve heard you can use bleach but I never have because of the smell. I’m sure there are other things you can use, but these have worked for me. The main thing is to rinse off whatever you’ve used, and let it dry for a day or two, before using the sealant


I recently bought a house with tile counters in the kitchen and bathrooms. They’re old but seem to be in pretty good shape and I want to keep them. I did the water test mentioned in the article and none of it beaded up, so I know there is no sealant on the grout. But before I seal them I need to clean them, and I'm wondering what should I clean them with? I don’t want to use anything that might interfere with the sealer adhering.


I just want to add that add that grout colors can be changed by using colored sealants. This may be common knowledge to many people, but it was a revelation to me that I could have the grout between the tiles on my kitchen backsplash whatever color I wanted!

I went with pink, just because I could!


You really can't overstress how important it is to make sure that the grout is clean and dry before you seal the grout is very important. I learned this the hard way when I was putting in bathroom tiles in my first house.

It was one of my first home DIY projects, and certainly not my best -- I thought it would be OK if I just let the grout almost dry (OK, it was still kind of wet, I admit it) and then seal it.

Well, five years later we were still living with mildew in our grout. We finally had to just take up the whole thing and do it again. I guess that really was one of those times where haste makes waste.

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