How to Seal Grout on Tile Floor: Step-by-Step Instructions

Sanded and unsanded grout are popular choices for most tiled surfaces. These types of grouts are porous and generally should be sealed to prevent staining.

Grout lines between tiles can easily collect water, dirt, oil, and other contaminants — especially in high-traffic areas of a home or business. Over time, grout lines will begin to look dark or black as grease, gunk, and grime build-up. This buildup can lead to odor complaints, mold and mildew growth, and contribute to dirt and germs being tracked throughout the facility on the bottoms of shoes.

Periodic cleaning of grout lines is an important part of any maintenance plan to remove stain-causing buildup and dirt. Additionally, it is recommended that grout be resealed about every 1-2 years to prolong its life and ensure long-term stain protection.

In this article, we’ll dive into what professionals need to know to prepare the tile floor, properly apply grout sealer, and select the best products for the job.

Preparing Floors Before Sealing

It’s important to prep the floor to ensure that the sealer will be correctly and successfully applied. Applying grout sealer to dirty grout lines will seal in the dirt and stains. If that happens, not only will it look terrible, but the grout sealer will have to be stripped so that the floor can be properly cleaned and resealed — a costly mistake that is completely avoidable.

Before applying grout sealer, follow these steps for proper cleaning of the floor surface and grout lines:

1. Set out appropriate safety signs before you begin.
2. Thoroughly sweep or vacuum the floor to remove loose debris. 
3. Use a cleaner specifically designed for grout. Dilute according to the label instructions and apply to the floor using a mop. Allow to dwell 10-20 minutes, but do not allow the product to dry.
4. Agitate the floor and grout lines using a floor machine, auto scrubber, counter-rotating brush machine (CRB), or grout brush.
5. Note: Some floor and grout cleaners do not require agitation. Be sure to read and follow the label instructions.
6. Rinse the floor using clean, warm water and extract the solution with a hard surface wand and extractor.
7. Speed-dry the floor using an air mover.

Now that your floor and grout lines are clean, you are ready to move on to the sealing process.

Types of Tile Grout and Grout Sealants

Grout comes in a variety of different types, each with unique characteristics and use cases:

• Sanded or unsanded grout: These types of grout are cementitious, meaning their main ingredient is cement. Because cement is porous, it’s susceptible to absorbing dirt and grime from everyday foot traffic more easily than other grout types. A sealer is recommended for these types of grouts.
  
  
• Epoxy grout: While more expensive, epoxy grout is generally more durable, stain- and moisture-resistant, and therefore a great choice for areas in a home or business that are exposed to moisture, like a bathroom shower wall or floor. Plus, epoxy grout often doesn’t need to be sealed, as its resilient nature is enough to keep tile flooring and walls looking great for a long time.

So, if you’re dealing with cementitious grout (which is most common), there are two types of sealers to consider:

• Penetrating sealers: This type of grout sealer is the most common and comes highly recommended for areas that are susceptible to moisture and other contaminants, as it effectively reduces the absorptive nature of cement-based grout. Our experts recommend a penetrating grout sealer for tiled floors and countertops.
  
  
• Non-penetrating sealers: On the other hand, non-penetrating sealers, or membrane sealers, are more appropriate for areas not as prone to dirt, grime, and water, such as kitchen backsplashes.

Steps To Seal Grout Tile Floors

Sealing grout, aside from helping keep it (and the tile itself) looking cleaner for longer, can also help prevent the growth of mold and mildew. Plus, sealing grout is relatively inexpensive compared to other floor care or renovation projects, so there are plenty of reasons to complete this crucial step.

The steps for sealing grout lines on most floors are the same regardless of the flooring material (ceramic, porcelain, natural stone, etc.). Check out the steps listed below, but always defer to the instructions on the product label for specific application steps or considerations:

1. Set out appropriate safety signs before you begin.
2. Thoroughly sweep or vacuum the floor to remove loose debris. 
3. Apply the grout sealer according to the label directions using a Grout Sealer Applicator Wand.
4. Allow the penetrating sealer to soak into the grout for 5-15 minutes.
5. Liberally apply a second coat of grout sealer, following the same process covered in the previous two steps.
6. Before the sealer sets completely, wipe up all excess residue from the surface of the tile using a clean, dry, and lint-free towel.
7. Note: If the sealer was not completely wiped off and a residue appears, simply wipe the entire surface with a clean towel dampened with sealer. If necessary, use a white nylon pad to loosen the residue and follow up with a clean white absorbent towel to remove it.
8. To achieve a full cure, the sealer must sit for 24-48 hours (though most grouts are cured enough for foot traffic sooner). Avoid exposing the floor to water for about a week. If you do need to spot-clean areas during this time, be sure to clean spills immediately and speed-dry the area with an air mover.

FAQ About Grout Sealing + Best Products and Tools for the Job

Jon-Don is here to help cover all your grout sealer and floor care bases. We’ve compiled a short but informative list of additional FAQs to help you understand more about sealing grout, including if it’s possible to seal old grout and how often it should be resealed.

Can You Seal Old Tile Grout?

Yes, although we recommend sealing grout as soon as possible after installation so that it’s preserved in its newest state — before it ever has a chance to become too dirty or damaged. That said, when sealing older grout, it’s important to give it a good cleaning first.

What Type of Grout Cleaner Works Best on Porous Tiles?

Natural stone tiles are porous. Cleaners with high acidity or other harmful chemicals can be absorbed by these tiles and cause staining, etching, or damage. For porous material, it’s best to use a cleaner with a neutral pH that’s specifically designed for natural stone, such as StoneTech® Stone and Tile Cleaner.

How Often Should You Reseal Grout?

Penetrating grout sealer breaks down over time and therefore needs to be replaced occasionally to keep floors looking their best. On average, grout in high-traffic areas should be resealed once every year or so. In low-traffic areas, you may be able to get away with resealing once every 2 or 3 years if you keep up with regular tile cleaning and maintenance.

What Is the Best Tile Grout Sealer?

The best grout sealer for your job will depend on a few factors: whether or not the tile grout being sealed is inside or outside, whether heavy-duty sealing is necessary, etc.

The following products come highly recommended for a variety of uses:

• StoneTech® Heavy Duty Grout Sealer
• StoneTech® BulletProof Sealer
• Miracle Sealants 511 Porous Plus Sealer
• Miracle Sealants 511 H20 Plus Sealer
• Miracle Sealants 511 Impregnator Sealer, 32 oz
• Endurable Penetrating Sealer

Jon-Don has everything you need for tile and grout projects, from products for sealing and cleaning to tools and equipment for re-application and more.

Grout Sealing Training and Education

Want to learn more about hard floor care? Check out our hard floor care classes. Learn from industry experts on how to care for all types of flooring, from stone to porcelain, luxury vinyl tile (LVT) to vinyl composite tile (VCT), and more!