How to Seal Grout: Basics and Application Guide

Keep Your Tile Looking Its Best in 5 Easy Steps

Closeup of gloved hand applying grout sealer

The Spruce / Jason Donnelly

Project Overview
  • Working Time: 1 - 3 hrs
  • Total Time: 1 - 2 days
  • Skill Level: Beginner
  • Estimated Cost: $15 to $75

Grout sealer is a necessary component of the tile installation process. It serves to prevent moisture and other contaminants from working their way into the grout and under the tiles. It's applied to the grout after it is thoroughly dry. There are different types of grout sealer for different areas so it's important to figure out what type of sealer you need before choosing a product.

Resealing grout is necessary but how often depends on the room and the surface. A high-traffic, water-prone floor, countertop, tub, or shower enclosure may need to be resealed at least once a year. A low-traffic area with minimal water contact, walls, or backsplashes may only need resealing every two or three years. Read on to learn more about how to use grout sealer.

Before You Begin

After installation of the tile, you should wait until the grout is 100 percent dry before applying the grout sealer. Any presence of moisture in the grout will prevent the grout sealer from soaking in. Keeping a freshly tiled room warm aids in curing grout.

Grout sealer is easy to apply but tedious. The smaller the tile size the more grout you will have. If you installed small mosaic tiles, for example, you're in for a lot of grout sealing. If you installed large format tiles, your sealing job will be exponentially easier and faster. This matters because using the brush or roller sealer applicators on an entire roomful of small tile can take a very long time. In this case, consider trying the spray-on type of grout sealer.

Grout should always be thoroughly cleaned before being sealed.

Types of Grout Sealer

There are two types of grout sealers and the type you use depends on the location of the grout.

  • Penetrating sealer: This is the most common type of grout sealer that soaks into the grout's surface to fill in the tiny pores but does not change the color or texture of the grout. However, these sealers also come in colors to enhance or rejuvenate the grout color. Use penetrating sealers in wet areas like the shower area or on a bathroom floor.
  • Non-penetrating sealer: This type of grout sealer, also called a membrane sealer, adds a coating to the grout's surface and gives it an aesthetic sheen or a new color. It's a good option for basic protection for areas that come into contact with minimal water or dirt, such as kitchen backsplashes, but it is not appropriate anywhere in a bathroom or water-prone area.

Tip

When choosing a product, be careful not to confuse grout sealer with tile sealer. Both types have topical and penetrating options. Grout sealer protects grout and tile sealer protects the face of the tile.

Application Methods

There are three methods you can use to apply grout sealer:

  • Brush on: The sealer itself is milky in appearance and is applied directly to the grout itself with a brush tip. You can also try a small foam brush for a smoother application. Avoid getting the grout sealer on the tile itself, though a bit does not really matter. The brush applicator is difficult to use because the sealer doesn't feed smoothly into the brush and sometimes requires you to go back and reapply in dry areas where the sealer failed to apply.
  • Roll on: Rollers allow you to keep moving down the tile seam line, with little or no reapplication efforts. Rollers are not perfect but may be better than brushes. The sealer remains relatively close to the seam line without slopping too far over onto the tile surface.
  • Spray on: If you dread the idea of laboriously following the grout lines with an applicator tip, spray on is an option, but it is not perfect, either. Spray-on sealers are supposed to work by allowing the sealer fluids to soak into porous materials, such as sanded grout, but not into smooth surfaces, like the glazed surface of ceramic or porcelain tile. So, even though some sealer will end up on the glazed surface, it should wear off over time, in theory. You pay the price for this convenience because you have more tile surface cleaning later on.

What You'll Need

Equipment / Tools

  • Clean cloth
  • Rubber gloves

Materials

  • Grout cleaner
  • Grout brush or old toothbrush
  • Grout sealer (brush on or spray)
  • Brush, foam sponge, or roller

Instructions

Overhead view of materials to seal grout

The Spruce / Jason Donnelly

How to Use Grout Sealer

  1. Clean and Dry the Grout

    • New grout needs to be fully cured before sealing. Check the grout's instructions to see how long it will take to fully cure so that there is no trapped moisture.
    • Examine existing grout for cracks that need to be filled in before sealing.
    • After fixing older grout, it needs to be thoroughly cleaned and also completely dry before sealing.
    Cleaning and drying grout before sealing it

    The Spruce / Jason Donnelly

  2. Apply the Sealer

    • Apply the sealer to the grout lines using a brush, foam sponge, or roller.
    • Completely cover grout lines uniformly.
    Above view of applying grout sealer with a sponge applicator

    The Spruce / Jason Donnelly

  3. Wipe Down Tile

    Most sealers require you to wait 10 minutes before wiping down the tile with a damp cloth to remove the excess sealer.

    Wiping down the tile after sealing the grout

    The Spruce / Jason Donnelly

  4. Add a Second Coat

    Adding a second coat based on the package instructions.

    Adding a second coat of grout sealer

    The Spruce / Jason Donnelly

  5. Allow Grout to Dry and Test

    • Allow the grout sealer to dry completely based on the package instructions.
    • Test its effectiveness by putting a few drops of water onto the grout to see if it beads up.
    • If it does not bead up, apply another coat of sealant. Continue to test until water beads up on the grout lines.
    • Allow the sealer to cure per the package instructions, which could be 24 to 48 hours or more. While the sealer cures, do not use, walk on, or clean the area.
    Testing the grout sealer to see if it has dried yet

    The Spruce / Jason Donnelly

    FAQ
    • Is it really necessary to seal grout?

      Yes, you need it, except when you happen to be using epoxy-based grout. Grout sealer is not needed with epoxy-based grout, because this type of grout naturally sheds water with no additives needed.

    • What happens if I don't seal grout?

      Grout is porous. If it is not sealed, it will absorb moisture that can lead to mold and mildew. Unsealed grout can also absorb bacteria, dirt, and stains. Sealing grout also helps you to avoid the costly and laborious project of regrouting.

    • How long does grout sealer last?

      It depends on the type of sealer you use and where it's located. Topical sealers break down and last for two to three years. Impregnated and penetrating sealers last much longer, about 15 years.

The Spruce uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. How Topical and Penetrating Sealers Protect Your Tile and Stone. Ceramic Tile Education Foundation.