How to Grout Backsplash Subway Tile

Grouting backsplash subway tile can transform your kitchen or bathroom by pulling together the look of your tile design. With proper technique and care, you can achieve clean, uniform grout lines that enhance the beauty of the tile. We will walk you through the entire process step-by-step, from preparing for grouting to sealing the finished product. With a bit of planning and effort, you can get stunning results.

What You Need to Grout Backsplash Subway Tile

Before starting any tiling project, it’s important to make sure you have the right tools and materials on hand. Here’s what you’ll need for grouting subway tile:


  • Choose an unsanded grout for grout lines 1/8″ or smaller, which is typical for standard subway tiles. Sanded grout contains sand particles and is used for wider grout lines.
  • A polymer-modified grout is a good choice for kitchens and bathrooms as it resists moisture and staining better than plain cement grout.
  • Choose a grout color that complements your tile. White and gray are popular choices for subway tile.

Grout Float

  • A rubber grout float is used to spread and work the grout into the grout lines. opt for one with a pointed tip to get into corners easily.

Grout Sealer

  • Using a grout sealer after installation will protect the grout from staining and discoloration. Choose a water-based sealer for a subway tile backsplash.

Grout Removal Tool

  • A grout saw or sharp utility knife makes it easier to remove old or excess grout.


  • Cellulose sponges are ideal for wiping up excess grout. Dampen them just before use.

Buckets & Containers

  • Have a bucket for mixing grout and several containers for holding water to rinse & dampen sponges.


  • Grout haze remover
  • Rags
  • Kneepads
  • Drop cloths
  • Paper towels
  • Eye protection & dust mask

Preparing to Grout

Completing these preparatory steps will set you up for success:

Let Mortar Cure

Before grouting, allow the tile mortar to cure fully – generally 48-72 hours. Grouting on uncured mortar can lead to cracks or color changes.

Clean Tile Surface

Use a sponge and water to wash away any dust, dirt, or debris left over from tile installation. Grout will not adhere to soiled tiles.

Remove Spacers

Take out all tile spacers from joints before grouting. Leaving them in place can lead to uneven grout lines.

Dampen Tile

Lightly dampen the tiles with a sponge just before grouting. This prevents the tiles from absorbing water from the grout too quickly.

Check Grout Coverage

Do a test area to ensure you have purchased enough grout for the project. Check that coverage matches manufacturer’s specs.

Protect Surfaces

Cover any countertops, floors, or walls near the backsplash to protect from splatters and spills.

Mixing and Applying Grout

Take care with grout mixing and application for best results:

Mix to Package Directions

Mix grout powder and water per manufacturer’s instructions. Only mix up as much as you can use in 30 minutes.

Apply With Grout Float

Use the grout float to spread grout diagonally across a section of the wall, holding it at a 45° angle and applying even pressure.

Pack Joints

Work the grout firmly into the joints with the float. Holding it at a 90° angle, move it in circular motions to fully pack the grout in.

Small Batches

Grout in 3-4 foot sections for best control. Don’t let sections sit too long before cleaning.

Consistent Depth

Keep grout to a consistent 1/8″ depth in the joints for uniform appearance. Deeper is not better.

Inside Corners

Use a small finger trowel to pack grout tightly into inside corners.

Remove Excess

Hold the float edge at a 90° angle and scrape off any excess grout sitting on the tile surface.

Cleaning and Finalizing the Grout

Proper techniques for cleaning up will prevent haze and produce clean grout lines:

Initial Wipe

Do an initial pass with a slightly damp sponge in diagonal motions. Rinse sponge frequently.

Hazy Film

Change water and rinse sponge often to prevent a hazy film from developing as you clean.

Minimal Water

Use as little water as possible during clean up to avoid discoloring the grout.

Check Corners

Inspect that all inside corners are packed fully and free of gaps or pinholes.

Soft Cloth

After the grout has begun to set up (1-2 hours), do a final light pass with a clean, soft cloth.

Avoid Smearing

Don’t overwork one area as this can cause smearing once grout starts to set.

Dry Microfiber

Follow with a dry microfiber cloth to polish off any remaining haze once grout is fully set.

Grout Sealing

Once dry, apply a grout sealer with a small paintbrush. This adds protection from moisture and stains.

Tips for Achieving Flawless Grout Lines

Attention to detail and workmanship makes all the difference in getting picture-perfect results:

Consistent Pressure

Maintain consistent, even pressure as you pack grout into joints for uniform appearance.

Match Bucket Grout

Try to use grout only from one bucket per section to avoid variances in color.

Work in Shade

Avoid working in direct sunlight which can cause grout to dry out too quickly.

Inside Out

On walls, grout from the bottom up so gravity helps keep grout in joints.

Minimal Grout Lines

Use tile spacers when laying tile to create the narrowest grout lines suitable for your tile size.

Grout Release

Apply a grout release or sealer to tile before grouting for easier cleanup and less staining.

Cure Time

Allow full curing time before sealing or exposing grout to moisture. This prevents weak spots.

Seal Annually

Reapply grout sealer annually or biannually to maintain protection on high-use backsplashes.

Grout Problems and Solutions

Even expert tilers sometimes encounter issues with grouting. Here are some common problems and ways to prevent or address them:


Causes: too much water in mix, grout applied too thick, rapid drying

Prevent with: proper mix consistency, thinner applications, shaded work area

Fix: rake out cracked grout, dampen, re-grout affected areas

Powdery Grout

Causes: poor mixing, low-quality grout

Prevent with: precision mixing, high-quality grout

Fix: rake out powdery grout, dampen, re-grout affected areas

Grout Haze

Causes: not wiping off excess before drying, poor cleanup

Prevent with: proper wiping technique, grout release

Fix: apply haze remover once grout is fully cured


Causes: moisture reacting with minerals in grout

Prevent with: sealing, proper mix ratios, cure time

Fix: dampen then scrub with stiff nylon brush


Causes: colored liquids absorbed by porous grout

Prevent with: sealing grout, careful cleaning

Fix: scrub with bleach mixture or specialized cleaners

Crumbling Grout

Causes: pressure washing, moisture damage, aging grout

Prevent with gentle cleaning, sealing, resealing

Fix: rake out crumbling grout, re-grout affected areas

Grouting Subway Tile Backsplash FAQs

What is the best way to get straight grout lines?

Use tile spacers when installing the tiles. Hold your grout float perfectly perpendicular to the joint as you pack in the grout.

How soon can I seal the grout after installation?

Wait the full recommended curing time, generally 3-7 days. Sealing too early traps moisture and can cause problems.

Is it better to grout vertically or horizontally?

On walls, vertical grout lines are easiest as gravity helps keep the grout in place. Grout horizontal joints even more carefully.

How do I prevent discoloration on my white subway tile grout?

Use as little water as possible when cleaning. Immediately wipe up spills. Reseal annually. Consider epoxy grout for maximum stain protection.

What is the easiest way to apply grout into inside corners?

Use a finger trowel, which is a small, pointed stainless steel trowel. Work in small sections to fully pack the corner before moving on.

Should I seal my grout before or after cleaning up excess?

Always seal after cleanup and once the grout has fully cured. Sealing during installation will make cleanup difficult.

Can I use a pre-mixed grout in a tube for subway tile?

Pre-mixed grouts are not ideal for floors or larger installations. For small backsplash areas, they can provide convenience. Review product limitations.

Is it better to grout subway tiles vertically or horizontally?

On walls, vertical grouting is the easier method. Grout horizontal joints carefully, maintaining consistent depth across entire rows.


Grouting completes your backsplash tile installation by creating clean, uniform joints between your subway tiles. While it requires careful technique, the right materials, and patience, the results are well worth the effort. Your kitchen or bath will enjoy a cohesive, pulled-together look. Prevent stains and exposure to moisture by sealing your grout lines annually. With proper care, your subway tile backsplash will look like new for years to come.