Grout Sealer: Basics and Application Guide

Shower Tile
Grout Sealer Is Especially Needed in Wet Places Like Showers. GregoryButler/pixabay by CC0

Grout sealer, a necessary component of the tile installation process, serves to prevent moisture from working its way into the grout and under the tiles. Grout fills seams between tiles. Most grout you will be using is called sanded, meaning that grout contains sand.

Sand is used by manufacturers not just because it is literally dirt-cheap but because it is a good material for what is a simple job: filling in a hole.

Grout is not needed to stabilize tile because mortar already holds the tile in place without any extra help.

Sand is porous, which means that grout is porous. Once grout has been applied and dried, it is ready to absorb any liquid that comes its way--like water.

By penetrating the grout with sealer first, you are pre-empting water and other liquids from penetrating the grout. Grout sealer is that simple.

Do You Always Need Grout Sealer?

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, no additives needed.

SpectraLOCK from Laticrete is one popular brand. Epoxy grout is more expensive and can be tricky to mix.

Is It Easy to Apply Grout Sealer?

Grout sealer is easy to apply, but tedious. The smaller the tile size, the more grout you will have. If you installed small mosaic tile, for example, you're in for a lot of grout sealing.

If you installed large format tile, 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 up a whole weekend. In this case, try the spray-on type of grout sealer.

Assessing Whether You Need Grout Sealer

Existing (not freshly installed) tile will occasionally need reapplication of grout sealer.

Highly trafficked floor tile will need grout sealer applied more frequently than other types of tile applications, such as wall tile. Tile kitchen countertops tend to need more frequent resealing than tile bathroom counters.

The best test is a simple one: place a few drops of water in your palm, then sprinkle that water at various places around the tile field. Grout areas that soak in water immediately need resealing. Areas where the water beads up and stands on the grout need no resealing.

How Long Should You Wait Before Sealing?

After installation of the tile, you should wait until the grout is 100% 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.

    Best Way to Apply: Brush vs. Roller vs. Spray

    Never apply grout sealer to the surface of non-glazed tile. Otherwise, the sealer will soak into the tile itself and never come out. You have three choices as to application: brushing it on, rolling it on, and spraying it on. 

     Brush OnRollerSpray On
    BasicsThe sealer itself is milky in appearance and is applied directly to the grout itself with a brush tip. Avoid getting the grout sealer on the tile itself, though a bit does not really matter.Rollers allow you to keep moving down the tile seam line, with little or no reapplication efforts.Dread the idea of laboriously following the grout lines with an applicator tip? Then, just spray it on. The theory behind spray-on sealers is that sealer fluids soak into porous materials (sanded grout) but not into smooth surfaces (the glazed surface of ceramic or porcelain tile). So, even though sealer will end up on the glazed surface, it should wear off over time, in theory.
    Easy or Hard?Hard. 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 sealer failed to apply.Easy. Rollers are not perfect, but they are better than brushes. The sealer remains relatively close to the seam line without slopping too far over onto the tile surface.Easy at first, hard later. You pay the price for this convenience because you have more tile surface cleaning later on.
    Buy On Amazon:

    AquaMix Grout Sealer Applicator

    Dupont Stonetech Professional Grout Sealer, 1 Quart

    M-D Products 12 Oz. Seal-A-Wheel 

    Dupont Stonetech Professional Grout Sealer, 1 Quart

    Homax Grout One Step Spray Grout Sealer