Is Bathroom Grout Waterproof Or Porous? [And Should You Seal It?]

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Tiling a bathroom can be a big undertaking. Sometimes grout can be an afterthought, but it is an integral part of the tiling process and not all grout is the same. One of the age-old questions asked by do-it-yourselfers is whether the bathroom grout is waterproof or porous? We dive into grout here; it’s not a simple answer. 

Whether or not bathroom grout is waterproof or porous depends on the type. The most common types of grout include cement-based, epoxy, and acrylic. Cement-based grout is porous and needs to be sealed. The only grout that is completely waterproof and doesn’t need to be sealed is epoxy grout. Acrylic grout is considered waterproof and doesn’t need to be sealed, but often the manufacturers say that it works best when used with a water-based sealer. 

There are several items to consider when deciding on the type of grout to use for a bathroom. The following details the advantages and disadvantages of cement-based, epoxy, and acrylic grout choices. Please keep reading to learn more! 

Gray bathroom tiles placed in a zigzag pattern, Is Bathroom Grout Waterproof Or Porous? [And Should You Seal It?]

The First Decision—Sanded or unsanded grout?

As its name suggests, sanded grout contains sand and gives it a gritty look and feel. Unsanded grout doesn’t contain sand. Because of the absence of sand, it is easier to get into smaller grout joints, less than 1/8″. It is stickier than sanded grout. It can shrink as it dries. The difference between sanded or unsanded grout comes down to the look you want for your tile.

Cement-based Grout

Cement-based grout is porous. It can be sanded or unsanded. If it is not sealed it will easily stain and water can be absorbed. Over time it can crack.

Despite its flaws, this choice is the easiest to install. It comes in a bag and is mixed with water according to the manufacturer’s instructions. If it gets hard to work with, more water can be added. It must be cleaned as you go with freshwater changed out regularly. Cement-based grout can be walked on the following day and should be sealed immediately after it is dried.

A tile setter applying grout to the tiles

Expoxy Grout

Epoxy grout gives the look of sanded grout. Epoxy grout comes in two or three parts that must be mixed specifically to the manufacturer’s instructions. It is imperative to not use water in the mixing process. Once mixed, it is the most difficult to install and takes a lot of elbow grease to get into the joints; however, once complete, it is waterproof.

Click here to see waterproof, white epoxy grout on Amazon.

Sealant is not to be used as it will cause yellowing. It is very uniform in color and is stain resistant. Ideally, it should be mixed in small batches as it hardens within twenty minutes and becomes very difficult to use. Make sure to use a rubber grout float that is specifically for epoxy grout. It takes two days to be completely dry. 

Acrylic Grout

Acrylic grout gives an unsanded look and resembles more of a caulk smooth finish. It does not need to be mixed. It comes in a premixed container that is ready to install as soon as it is opened. Acrylic grout is dry within 24 hours but requires three days before it can be exposed to water. Use a rubber grout float for installation.

Click here to see a rubber grout float on Amazon.

The downside to acrylic grout is that it can shrink and crack, especially where the joints meet another surface like the base of the countertop and the backsplash in a kitchen. In addition, it can be very difficult to clean off the tiles. Although it does not require sealing, manufacturers recommend that it “performs best with a water-based penetrating sealer.”

As with all applications of grout, make sure that you clean the grout off the tiles as you apply, never leaving the grout to set up for more than 20 minutes. Paying careful attention to the requirements on the manufacturer’s instructions can be the make or break on the success of your grouting project. 

Does Bathroom Tile Grout Need To Be Sealed?

A blue tiled bathroom lavatory with white tiles

A bathroom must be sealed annually if cement-based grout is used, but every six months is the better practice. This will help prevent mold and mildew from getting into the joints and will help to prevent stains. It is difficult to tell the difference in grout choices in previously tiled bathrooms. It is best to assume that you need to seal the tile because the majority of the tile is laid with cement-based grout, even by tile contractors.

If you have an older tile job that needs repair, check out this post: 6 Shower Tile Repair Solutions [Easily Fix Cracks, Chips, And Holes]

What Type Of Grout Sealer To Use In A Shower?

A modern round shaped shower head

There are three types of grout sealers: impregnating or penetrating sealer, a topical sealer, and a sealer as an additive when mixing the grout. Impregnating or penetrating sealer soaks into the grout or the natural stone tile to help prevent stain and moisture. It has a longer duration of three to five years. Please note that natural stone tile really should not be used in bathrooms or high water areas due to its very porous nature. 

Topical sealers adhere to the top of the grout or tile and seal for up to a year. Each must be reapplied according to the manufacturer’s instructions.

A sealer additive can be used in mixing cementitious grout in place of water.  This helps to make the grout more water and stain-resistant and durable.

How Do You Waterproof Shower Grout?

In high water areas like showers, it is best to choose an epoxy grout. It is completely waterproof and will not allow water or stains to penetrate. Otherwise, an impregnating or penetrating sealer is the best choice of sealer to use in the shower.

For more information regarding the best tile for showers, check out this post: Best Type Of Tile For Shower Walls

What Is The Purpose Of Grout Sealer?

Sealing helps to prevent moisture absorption and staining. It also helps to prevent mold and mildew from getting into the porous cement-based grout. You can add a sealer additive when mixing the grout, or you can seal over the top of the finished grout. Sealer must also be applied prior to grouting natural stone or marble.

When deciding on whether to use a sealer, you will want to make sure to follow the specific directions on the grout itself because each one is just a little bit different. Sealant doesn’t make grout waterproof, just resistant. Sealant must be applied regularly.

Do I Need To Seal Waterproof Grout?

You must not seal epoxy grout. Using sealer on epoxy grout will turn it yellow. Acrylic grout also does not require sealant; however, manufacturers say it works best if it is sealed with a water-based sealer.

In Closing

Grout can be an afterthought or it can be overwhelming with all the options to consider. It is one of the most important aspects of a tile project. Whether grout is waterproof or porous depends almost entirely on the type of grout you choose. It is imperative to read and follow the manufacturer’s instructions for the installation of any type of grout because not all grout is created equal.

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