What is Grout and What is Mortar?
Grout and mortar have similar properties, which cause people to confuse the two. Mortar is the adhesive used to hold tiles to a surface or substrate. Grout, on the other hand, is the substance applied between the tile spaces to fill and seal the gaps. There’s a mortar or grout product for every type of tile and tile location. It’s important to choose the right product for the job.
Before you shop for grout or mortar, you’ll need to know:
- Tile Material: Is it stone, ceramic, glass or metal? Different tile types have different requirements.
- Location: Is the area indoors or out, wall or floor, wet or dry? Note: Submerged areas, such as pools and fountains, require specific mortars.
- Purpose: Is it for drywall, backer board or other tile?
- Square Footage: How large is the area being tiled?
- Tile Size: Large, heavy tile needs specific mortar types.
Mosaic tile can suffice with a less powerful adhesive. The tile industry designates a tile with any edge longer than 15 inches a large-format tile. Anything smaller is considered small-format tile. These two classes are important to know as they affect the mortar and trowel you’ll use for your project.
Using the correct trowel and mortar is critical to a successful tile project. If mortar is applied incorrectly, your tiling project could fail. Floor or wall, indoors or out, tile type and size are factors.
Types of Mortar
Mortar is available premixed for use right out of the container or in powder form. The powder is mixed with water or a polymer additive. The additive provides additional flexibility for indoor or outdoor use plus improved adhesion. Thinset mortar is also available, which is a cement-based product that works well with level, flat surfaces.
Rapid-set mortar hardens very fast and is best left to the pros. Always read the product specifications to confirm which surfaces and substrates you can apply mortar to, what temperature is recommended for the job and what type of trowel is required.
If you're installing glass tile, the surface underneath the tile will be visible. Use white mortar and a straight-edge trowel (rather than notched) for the best appearance.
Types of Grout
Grout is generally classified as sanded (cementitious) or unsanded. Both can be used indoors or outdoors and on walls or floors. Grout is available premixed and ready to use or in powder form that you mix with water as you need it. If you use powdered grout, don’t use too much water when mixing as this could weaken the grout. Read and follow the product instructions carefully.
Like tile, it’s a good idea to buy extra mortar and grout to ensure you’ll have enough to finish the project.
- Sanded Grout: Use sanded grout for grout joints from 1/8 inch to 5/8 inch to resist cracking and shrinkage.
- Unsanded Grout: Use unsanded grout for grout joints up to 1/8 inch. Use only unsanded grout with glass, polished marble or metal tile to avoid scratching the tile.
- Premixed Grout: Ready to use grout that does not require mixing and is a no-mess alternative to traditional grout.
- All-in-One Grout: Replaces the need to use sanded and unsanded grout for the same project.
- Acrylic Grout: Acrylic grout is a great option for wet areas like decks and showers. It’s intended to be mildew-resistant and retains its color well.
- Epoxy Grout: Epoxy grout is less do-it-yourself-friendly than other types. It’s a common choice for countertops due to its hardness. Epoxy grout doesn’t need to be sealed.
Grout Colors
While the tile that you use on your floors or walls is important, the grout you choose is equally important. Tiles don’t completely cover the entire floor or wall area, so the gaps between each tile are filled with grout. Grout complements the tile and floor and protects them from water and moisture. The most common colors are black grout and white grout.
Pre-colored grout gives you the ability to add a custom-designed look to your tiles. When grouting tile, you can use grout to match the tile color and create a cohesive look or use a contrasting grout color to set the two apart — the choice is yours. There’s a range of colored grout to choose from to meet your needs.
Black grout works well with white and other light-colored tiles when you want to create a high-contrast look. This contrasting look also works well if you’re creating a pattern such as herringbone, brick bond or hexagon. If you’re going for sheer drama, black tile with black grout can’t be beat.
Brown grout is a good, solid color that pairs well with subway tile. It’s a great neutral color that adds warmth to a space. For rooms with brick, leather or wood, brown coordinates subtly without being too overpowering.
To unify a design, choose a warm shade, like gray or off-white grout, or a shade that’s closely matched or two shades lighter.
Choosing a grout color that’s the same color as the tile will help make the space feel larger. For example, choosing white grout to go with white tiles, such as subway tile in a bathroom, visually opens up the room. White also looks good with gray, blue-gray and light gray tiles.
Multicolor tiles can be difficult to pair with grout, but there’s an easy way to determine what color may work best. Select the most prominent color in the tile and go with a similar shade of grout. For example, a shade of orange grout works for tiles that are a blend of grays, greens and rusty oranges, unless you want to go for contrast.
Tintable grout is a newer alternative to pre-colored grout in indoor applications. Tints are added to a light or dark grout base for a custom color.
To get a better feel for how any grout will look with the tile before you buy, look at the tile and grout side by side. Make sure the grout color you choose can be used with your tile. A few key points to remember:
- More porous tile could absorb coloring from the grout.
- Lighter colors often show stains more easily unless your grout is sealed.
- Darker grout may fade over time.
Grout Sealant
Sealing grout is an important step in the grouting process and should be done as a final step to prevent staining, keep moisture out, and prevent mold and mildew. A grout additive will increase stain resistance. Grout sealants are available in three application choices: spray, brush and roller. When selecting a grout sealant, know which type you need: a penetrating grout sealer or a nonpenetrating grout sealer.
A nonpenetrating grout sealer is a surface sealer that offers a basic layer of protection. It prevents liquids from penetrating past the surface seal. This type of sealer is best for kitchen backsplashes and floors.
A penetrating grout sealer is absorbed into the grout and coats the inside of the pores, which keeps out moisture. This type of sealer is ideal for areas that are prone to dampness, such as bathrooms.
Look for a grout sealer that’s designed for your tile material. Make sure you allow the grout to cure before applying it.
For grout curing time, see the grout package label for details.
Preparing for Your Tiling Project
Before you start your tiling project, make sure the area you plan to tile is prepped. The surface must be clean, level, flat and solid (no flex).
To level a floor surface, knock down any high spots with a sander (wood subfloor) or grinder (concrete subfloor). Use a pourable self-leveling underlayment product to create the level surface necessary for tiling.
Follow cleaning, patching, leveling and any other product-specific preparation guidelines to ensure adhesion. When applying mortar and grout, always note the products’ drying and curing times.