Grout fills seams between tiles. Most grout you will be using is called sanded, meaning that grout contains sand.
Sand is used by manufacturers because it is literally dirt-cheap and 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. It 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.
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?
Easy, but tedious. The smaller the tile size, the more grout you will have. If you installed 1" tile, you're in for a lot of grout sealing; if it's 12" or 16" tile, not so much.
This matters because using the brush or roller sealer applicators on an entire roomful of 1" sized tile can take up a whole weekend. In this case, try the spray on type of grout sealer.
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.
|Brush On||Roller||Spray On|
|Basics||The 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 (i.e., sanded grout) but not into smooth surfaces (i.e., 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?||The brush applicator is difficult to use because 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.||Rollers are not perfect, but they are better than brushes. Sealer remains relatively close to the seam line without slopping too far over onto the tile surface.||You pay the price for this convenience because you have more tile surface cleaning later on.|
|Buy On Amazon:||Homax Grout One Step Spray Grout Sealer|