How to Seal Grout: Basics and Application Guide


Grout plays a critical role in tile installations by filling the spaces between tiles, known as joints. Not only does grout hold the tiles together and prevent moisture from seeping underneath, but it also contributes to the overall look and design of the tiled surface. However, because grout is porous, it can succumb to staining, cracking, and erosion over time. Applying a grout sealer creates a protective barrier that keeps grout looking fresh and prevents damage.

Sealing grout may seem daunting to DIYers, but it is actually a straightforward process that anyone can master. This comprehensive guide will walk you through everything you need to know about grout sealing, from understanding the benefits to step-by-step application instructions. Read on to learn the basics of how to seal grout for a revitalized tiled surface.

Why Seal Grout

Here are the main reasons you should make grout sealing a regular maintenance practice:

Prevent Staining

Grout is naturally porous, meaning it soaks up liquids and dirt easily. Spills like coffee, juice, oil, grease, and dirt will quickly stain unsealed grout. A grout sealer provides a waterproof and stain-resistant barrier. Sealed grout repels stains so they can be easily wiped away without leaving a trace.

Stop Moisture Absorption

Unsealed grout allows water to penetrate below the surface. Excess moisture can lead to mold and mildew growth in the vulnerable joint space. Sealing grout keeps water on the surface so it evaporates instead of being absorbed. This moisture protection extends the life of your grout.

Limit Cracking and Erosion

As grout ages, especially in high-traffic areas, it is prone to cracking under stress and pressure. Temperature fluctuations and exposure to water also cause deterioration over time. A grout sealer strengthens grout and makes it more flexible and resistant to damage.

Enhance Appearance

With consistent sealing, grout will maintain its like-new appearance for years. The sealer prevents dirt buildup in the joints, keeping grout lines looking clean and uniform. Sealing also enhances grout color by providing a slight sheen.

Extend Grout Life

The preventative maintenance provided by grout sealing will maximize the lifespan of your grout. Stopping water absorption and fortifying the grout against cracking will keep it intact and usable for longer without needing repairs.

Choosing a Grout Sealer

Once you understand why sealing grout is essential, the next step is selecting the right sealer for the job. There are a few key considerations when choosing a grout sealer product:

Application Method

  • Brush-on sealers – Applied manually with a brush. Offer more control over application.
  • Spray sealers – Applied with a spray bottle nozzle. Faster to apply on large projects.
  • Roll-on sealers – Applied with a paint roller. Good for broad application.

Dry Time

  • Penetrating sealers – Absorb into grout pores. Fast drying time of 30-60 mins.
  • Topical sealers – Sit on grout surface. Require 12-72 hours curing time.


  • Matte finish – Provide a natural, non-glossy look.
  • Glossy finish – Enhance grout color with a subtle sheen.

Frequency of Reapplication

  • Short-term sealers – Last 3-6 months. Require 2+ applications per year.
  • Long-term sealers – Protect for 3-5 years before reapplying.

Be sure to read the product details to understand the sealer’s specifications before purchasing. Talking to a knowledgeable sales associate at your local home improvement store can also help you choose the optimal sealer for your project.

What You’ll Need

Gather these supplies before starting your grout sealing task:

  • Grout sealer product
  • Personal Protective Equipment (gloves, safety googles, mask)
  • Paintbrush, paint roller, or spray bottle based on application method
  • Clean rags
  • Bucket of water
  • Vinegar or ammonia
  • Optional: fan, drop cloth

Check the sealer instructions for any special preparation or equipment recommendations. For example, some sealers require washing grout with a cleaner before application.

Prep Steps

Proper prep work ensures the sealer adheres well and provides maximum protection:

Clean the Grout

Remove any dirt, debris, grease, or soap scum from grout lines using a stiff-bristled grout brush, vinegar, ammonia, or degreasing cleaner. Rinse thoroughly with water and allow to fully dry.

Cover Surrounding Surfaces

Sealers can easily stain tile, natural stone, wood, and other surfaces. Cover nearby areas with a plastic drop cloth or towels. Masking tape can also protect walls and baseboards.

Ventilate the Space

For indoor application, open windows and doors and use fans to circulate air. Some sealers have strong fumes. Proper ventilation prevents buildup of vapors.

Read Label Instructions

Check the sealer label for any special prep steps like cleaning with an etching solution or acid wash. Follow all manufacturer directions.

Test on Inconspicuous Area

Apply sealer to a small, hidden section of grout to check for any discoloration or adverse reactions with the grout before treating the entire area.

Now it’s time to start sealing once prepped!

How to Apply Grout Sealer

Follow these key steps for proper application of the sealer:

Step 1: Apply Thinly and Evenly

Using a paintbrush, roller, or spray bottle, apply a thin coat of sealer in a back and forth motion over the grout joints. Avoid puddling. Spread evenly so all grout absorbs product.

Step 2: Let Sealer Penetrate

Allow 5-10 minutes for sealer to absorb into grout pores. Reapply to any areas that look dry. Grout should look damp but not soaked.

Step 3: Remove Excess

Completely wipe away all sealer pooled on tile or grout surface with clean rags before it dries. Going over the floor again helps remove missed excess.

Step 4: Allow Proper Cure Time

Follow manufacturer’s instructions for drying time. Most sealers need 30min to 2 hours before reapplying a second coat or 12-72 hours for full curing.

Step 5: Apply Second Coat (Optional)

For maximum protection, apply a second thin coat in a perpendicular direction from the first coat. Let fully cure.

Step 6: Clean Tools

Rinse out brushes, rollers, and spray bottles thoroughly with water to remove residual sealer and prevent clogging before it dries.

And that’s it! With these simple application tips, you can seal grout like a pro. Be sure to allow full curing time before using the tiled area. Avoid walking on floor sealers or wetting countertop sealers during the recommended drying period.

Grout Sealing Tips & Tricks

Follow these additional pointers for the most flawless sealing results:

  • Only apply sealer to fully cured and clean grout, never right after grouting.
  • Test first in an inconspicuous spot to confirm color and compatibility.
  • Apply when temperatures are between 50-90°F for proper absorption and drying.
  • Never shake the sealer container to avoid bubbling. Gently stir instead.
  • Add more coats every few years or whenever grout appears dirty again.
  • Use solvent-resistant tools like natural bristle or foam brushes.
  • Thoroughly wipe up spills immediately since sealers aren’t 100% impenetrable.
  • Use an epoxy-based sealer for extra waterproofing in bathrooms and kitchens.
  • Turn off overhead fans during application to prevent uneven drying.
  • To avoid trapping fumes indoors, seal external grout on a dry, low-wind day.
  • Wear a protective face mask, gloves, and goggles during application.
  • Work in small sections for easiest application and removal of excess before drying.
  • Avoid standing water on newly sealed grout for 24-48 hours to prevent softening.

Troubleshooting Grout Sealers

If your sealed grout develops any problems down the road, here are solutions for common issues:

Problem: Sealer appears streaky or uneven.

Solution: Wipe surface with a rag soaked in mineral spirits to level out and soften sealer.

Problem: Grout has a shiny plastic look.

Solution: Too much sealer was applied. Gently scrub to remove top layer and reduce shine.

Problem: Sealer comes off when wiping.

Solution: Do not apply sealer too thickly or before full grout curing time of 28 days.

Problem: Grout color is altered or whitened.

Solution: Test sealer on spare tiles first. Use an alternate clear sealer instead.

Problem: Grout seals but then quickly stains again.

Solution: Reapply sealer more frequently every 6 months and wipe spills quickly.

With the right sealing techniques and products, you can keep your grout looking pristine for years before needing to reseal. Refer back to these tips anytime you need to revitalize old, damaged grout. Understanding the basics of how to seal grout transforms this maintenance task into an easy DIY project.

Frequently Asked Questions

Here are answers to some common questions about sealing grout:

How soon can I seal grout after installation?

Wait a minimum of 72 hours for grout to fully cure before applying any sealer. 28 days is best for complete curing.

Should I seal sanded vs unsanded grout differently?

No – the same sealing process applies to all types of grout. Match the sealer to the grout material.

What’s the difference between sealing grout vs sealing tiles?

Grout sealers penetrate porous grout while tile sealers create a protective layer on impervious tile surfaces.

Should I seal grout before or after cleaning?

Always clean grout thoroughly before sealing so the sealer can properly soak in.

How long does grout sealer last before reapplying?

Durability depends on the sealer but averages 3-5 years for long-term sealers and 3-6 months for short-term sealers.

Can I apply grout sealer outside?

Yes, exterior grout can benefit from sealing. Avoid windy days and use a spray bottle for easiest application outdoors.

Should I seal all my grout or just the problem areas?

Sealing all grout will provide complete protection. Focus on high-moisture areas first if only doing spot treatment.

What’s the white haze on my sealed grout?

Whitish grout residue is typically caused by excess sealer or moisture being trapped underneath the topcoat.

Can I apply grout sealer over existing old sealer?

Yes, reapplying sealer over previously sealed grout will refresh the protective coating.


Regular grout sealing provides immense benefits by keeping grout looking clean and new while also extending its lifespan. While the array of sealers available can seem overwhelming at first, you can easily master grout sealing techniques with a little know-how. Following the preparatory, application, and troubleshooting tips covered in this guide will help you achieve professional-looking results.

Consistently maintaining your grout with sealing every few years prevents permanent stains and costly replacements. Don’t wait until grout is already crumbling and discolored to start sealing it. Make grout sealing a priority throughout the life of your tiled surfaces. Achieving grout that looks freshly installed for years to come is readily attainable with the simple How to Seal Grout: Basics and Application Guide steps outlined above.