Grout and Sealer Guide: Choosing, Sealing and Keeping Tile Looking Right

Grout and sealer guide

What grout does and why it fails

Grout fills the joints between tiles. It locks the tiles in place relative to one another, protects their edges from chipping, keeps debris out of the gaps and gives the surface a finished look. It is not a waterproofing layer, even though many people treat it as one.

Because grout sits at the surface of a floor or wall, it takes the brunt of everyday life. It gets wet, soapy, stained by food and drinks, scrubbed with cleaners and walked on. Over time, ordinary cement based grout can darken, crack or crumble, especially in showers, kitchens and entries.

Failure usually has one of a few causes: the grout was mixed or installed incorrectly, the joints were too narrow or too wide for the product, the surface beneath moved, or the grout was never sealed or cleaned properly. Understanding these causes helps you choose a type and a care routine that suit your room.

If your existing grout has changed color, our page on grout discoloration and staining looks at common causes in more detail.

Cement based grout

Cement based grout is the traditional choice. It is a mixture of cement, fine sand or other fillers and sometimes polymers, mixed with water and pressed into the joints. It comes in a very wide range of colors and is familiar to nearly every installer.

The key feature is that it is porous. Even when cured, cement based grout has tiny channels that absorb water and anything dissolved in it. This is why it stains and why it often needs sealing. Polymer modified versions resist staining better than plain mixes, but they are still more porous than epoxy.

Cement based grout comes in sanded and unsanded forms. Sanded grout contains fine sand and is used for wider joints, because it resists shrinking and cracking. Unsanded grout is smoother and used for narrow joints and for delicate surfaces that sand could scratch, such as some polished stone.

This type is easy to work with, widely available and cost friendly in general terms, and it suits many dry or moderately wet areas when properly sealed and maintained. In very wet or heavily used spaces, it asks more of the owner.

• Cement based grout comes in many colors and suits most rooms when sealed.
• Sanded grout is for wider joints and unsanded for narrow ones.
• Polymer modified mixes resist stains better than plain cement mixes.
• It remains porous, so sealing and cleaning habits matter.

Epoxy grout

Epoxy grout is made from epoxy resin and a hardener, usually with fillers. When the parts are mixed, they cure by a chemical reaction. The result is a dense, non porous grout that resists staining, water and many chemicals without needing a sealer.

It is popular for showers, kitchen counters and backsplashes, commercial style kitchens and places where cleanliness matters. It holds color consistently and resists the dark mildew lines that can form in cement grout.

The trade off is the installation. Epoxy grout has a short working time, hardens in the container if left too long and requires precise mixing and cleaning. Excess must be removed before it cures, because hardened epoxy is difficult to take off tile. It needs an experienced installer and is usually more expensive than cement based types.

Epoxy is also less forgiving of movement. It is stiffer than some cement grouts and, if joints are too narrow or the tile surface is very porous, can be harder to work with. Ask your installer which product and which technique they plan to use.

Other grout types and special products

Between cement and epoxy sit several other options. Urethane grouts are premixed, flexible and resist staining, and some come in ready to use form. Furan and other specialty resin grouts exist for industrial settings and are rarely used in homes. Premixed cement grouts are sold in tubs and aim for convenience.

Some manufacturers offer single component stain resistant grouts that combine cement with additives to repel water and stains without a separate sealer. They can be easier to use than epoxy, though their performance depends on the product and installation. Read the technical data and follow the instructions closely.

Flexible caulk is a different material from grout, and it has a different job. Wherever two planes meet, such as the corner of a shower or the junction of a counter and backsplash, a flexible sealant is used instead of grout so it can move without cracking. Using rigid grout in a corner is a common cause of cracks.

Colored caulks that match the grout are made for exactly this reason. Ask that corners and changes of plane be finished with sealant, and plan to renew it from time to time as part of ordinary upkeep.

Movement joints in large floors follow the same logic. Where a tiled floor is wide or meets a wall, a column or a different material, a flexible joint lets the surface expand and contract without cracking the tile. Ask your installer to show on a plan where these joints will fall and what color sealant will be used, so the result looks planned instead of like an accident.

Joint width, tile type and grout choice

The width of the joint affects grout choice and how the finished surface looks. Wide joints use sanded grout, which resists shrinkage. Narrow joints, common with rectified porcelain, use unsanded or specialty grouts, and the manufacturer sets a minimum joint size for each tile.

Tiles with soft or delicate surfaces, such as some polished marble and glass, can be scratched by sanded grout. Natural stone is also porous and can absorb pigments from colored grout, so test or use a sealer before grouting. Ask your installer what precautions they take with your particular tile.

Large format tile has fewer joints, which changes how much grout there is to maintain. Our large format porcelain tile guide explains how bigger tiles affect layout and joints, and our overview of tile types for Florida homes covers other materials.

Pick the grout after the tile. Samples of tile and grout together, viewed in the room's light, tell you much more than separate color chips.

Choosing grout color

Grout color shapes the entire look of a tiled surface. A color close to the tile blends the lines and makes the surface look continuous. A contrasting color outlines each tile and emphasizes the pattern, which suits traditional looks, subway tile and handmade tile, though it also highlights imperfections in the layout.

Practical issues affect color too. Very light grout can show stains and dirt in kitchens and entries. Very dark grout can show soap residue, mineral deposits and efflorescence, a white powder that can appear on cement based grout. A mid tone grout often looks fresh for the longest time.

Consistency matters as well. Cement grout can vary slightly in color from batch to batch depending on water content and curing, and a floor grouted over several days can show shade differences. Ask that grout be mixed carefully and cured evenly, and consider whether epoxy, which holds color more reliably, is worth considering for a high visibility surface.

Look at actual samples with sealer applied if possible, since sealing can deepen the color. Always view in the light the room really has.

Keep a record of what you chose. Write down the grout brand, color name, joint width and sealer on a card and keep it with your other home papers. When it is time to touch up or repair a joint years later, matching an unlabeled grout by eye is difficult, and a clear record saves time and avoids mismatched patches in the middle of a visible floor.

What sealers do and do not do

A sealer is a liquid applied to grout or stone that soaks into the surface and slows the absorption of water and stains. It does not create a skin on top of the grout. Instead, it partly fills the tiny pores so liquids stay on the surface long enough to be wiped away.

Sealers do not make grout waterproof or stain proof. They buy time. A spill that sits on a sealed surface for a short period is far less likely to soak in, but it can still stain if left. Sealed grout also still needs regular cleaning.

There are several kinds. Penetrating sealers, also called impregnators, soak into the material and are the most common for grout and stone. Topical sealers form a thin film on the surface and can change its look, sometimes adding sheen. Some are made for particular stones or for specific uses such as showers or exterior areas.

Check the label for what the sealer is meant to protect and what it should not be used on. Epoxy grout generally does not need sealing, and some tile surfaces should never be sealed, so follow the instructions for each material.

How and when to seal

Timing is important. New cement based grout must cure before a sealer is applied, and the maker will state how long that takes. Sealing too early traps moisture and can cause hazing or poor absorption. Tile surfaces should be clean and dry, with no wax, soap film or old sealer in the way.

Application is usually done with a small brush, applicator bottle or cloth, working along the joints and wiping excess from the tile surface before it dries. Dried residue on glazed tile or polished stone can leave marks that are difficult to remove, so keep a clean cloth in hand and work in small sections.

Reapplication depends on use and product, and a note on your calendar helps you remember. Showers, kitchen counters and busy entries may need resealing more often than a bedroom floor. A simple test is to place a few drops of water on the grout. If the water beads, the sealer is working. If it darkens the grout right away, it may be time to reseal.

Natural stone has its own schedule and needs. Our countertop materials guide explains how stone surfaces differ and why some need sealing more often than others.

Humid Florida rooms and grout

Humidity changes the way grout behaves. Damp air means surfaces stay wet longer, which feeds mildew in porous grout and in the soap film that builds up on it. Bathrooms without strong ventilation are the usual trouble spots, but laundry rooms, kitchens and covered patios have problems too.

The strongest defenses are practical. Run the bathroom fan during and after showers, squeegee wet walls, wipe splashes and avoid leaving damp towels in a heap. A small habit such as opening a window or running a dehumidifier in a closed laundry room can make a noticeable difference to how long grout stays damp. Our article on moisture planning in Florida homes explains how ventilation, materials and habits work together.

In showers, consider the whole system, not only the grout. A sound waterproofing layer behind the tile protects the structure even if grout lets some water through. Our guide to shower design options explains how the layers work.

Coastal air carries salt, and salt can affect some sealers, metal finishes and stone. Entries and outdoor tile also see sand and grit, which wears grout down sooner. For an entry that is rinsed often, a dense grout and a doormat outside can reduce the damage. Choose products suited to the exposure and clean regularly.

Cleaning, repair and regrouting

Regular cleaning keeps grout looking fresh. Sweep or vacuum floors to remove grit, then mop with a pH neutral cleaner suited to your tile and grout. Avoid harsh acids, which can eat into cement based grout and damage stone, and avoid bleach on colored grout. Test any product in a small area first.

For stained grout, soft brushes and gentle cleaners are the first step. Persistent discoloration may be a sign that moisture is trapped or that the grout is worn. Our page on maintenance after a remodel offers routines that apply here.

Cracked or missing grout should be fixed, because water can get behind the tile. Small areas can sometimes be repaired by removing the damaged grout and refilling the joint. Large areas of failure may mean movement or a hidden problem, as explained on our cracked or loose tile page.

Regrouting removes the old grout and replaces it, which can refresh a floor or shower without replacing the tile. It needs care to avoid chipping edges, and the choice of new grout must be compatible with the tile and joint width.

Planning grout and sealing with us

Grout seems small, but it affects looks, cleaning and durability. We begin with a call where you tell us about the property, the space and your priorities. We talk through layout, materials, storage, lighting and existing conditions, then build the plan and selections, including grout type, color, sealing and the sealant used at corners.

Before work begins, we go over the plan and the information needed. Our backsplash and tile and bathroom remodeling pages explain how we approach tile work in kitchens and baths.

Permit and approval requirements vary by city, building and community. Ask your city building department and, if you have one, your condo or homeowner association what applies to your project.

When you are ready to talk about your own tile, use the call button on this page and tell us about the room.

Questions and answers