How to Grout Stone Tile Backsplash

Grouting a stone tile backsplash can seem intimidating, but with the right tools and techniques, it can be a straightforward DIY project. Properly grouting a stone tile backsplash not only enhances the look of your kitchen or bathroom, but it also seals and protects the tiles.

What You Need to Grout a Stone Tile Backsplash

Before starting to grout a stone tile backsplash, assemble all the necessary supplies:

Grout – Choose an unsanded grout for most stone tiles like marble, travertine, limestone, and slate. Make sure to get a grout color that matches or complements the color of your stone tiles. White and gray are popular grout colors for stone.
Grout float – A grout float has a flat rubber edge that lets you spread and work the grout into the tile joints. Get a float sized for your tile joints, usually 1/4-inch or 1/8-inch.
Grout sealer – Using a grout sealer after installation will protect the grout from stains. Look for a water-based sealer made for stone tiles.
Sponges – Have several clean sponges for wiping up excess grout. Dampen them just before use.
Buckets – Two buckets are ideal, one for grout and one with clean water for rinsing sponges.
Old towels – Lay down towels to kneel on and wipe your hands on while grouting.
Trowel – A trowel helps with scooping and applying the grout.
Drop cloth – Cover any countertops or surfaces under your backsplash area.
Grout haze remover – In case of grout haze, have a chemical cleaner made for removing haze from stone.
Caulk – Use a flexible caulk to fill any gaps along countertops, sinks, or edges.

Prep Work Before Grout Application

Proper prep work is key to achieving smooth, even grout lines on your stone tile backsplash:

Allow mortar to fully cure – Let tile mortar dry for at least 24-48 hours before grouting stone tiles. This prevents tiles from shifting.
Clean tiles – Use a pH-neutral tile cleaner and damp sponge to remove any dirt, residues, or films from surface of the stone tiles. Rinse well.
Tape off walls – Use painter’s tape to mask off walls above the backsplash. This keeps them clean from splatters.
Fill gaps with caulk – Run a flexible silicone caulk along all joints between tile and countertops, sinks, or walls.
Plan your approach – Grout in sections for easier manageability. Start at the bottom and work upwards.
Have sufficient lighting – Proper lighting lets you see joints and wipe up grout thoroughly.
Clear surroundings – Remove everything from counters and backsplash area to prevent staining.

Mixing and Applying Grout for Stone Tiles

Mixing and applying grout takes a bit of practice to get the right consistency and technique:

Read manufacturer’s instructions – Follow product directions for exact mix ratio and drying times.
Use two buckets – One for dry grout, one with water. Measure carefully.
Mix to toothpaste consistency – Add powder to water little by little. Mix just enough for one section.
Let it slake – Allow grout to sit 5-10 minutes after mixing so polymers activate.
Apply grout across tiles – Use the grout float and work diagonally across the tiles to fill joints.
Pack grout into joints – Push firmly to fill all gaps and voids. Take care on delicate stone.
Remove excess grout – Hold float at a 90° angle “on edge” to scrape off excess grout.
Wipe diagonally – Use a lightly dampened sponge to wipe across tiles diagonally. Rinse sponge frequently.
Check for voids – Look for unfilled spots as you clean. Re-apply grout as needed.
Avoid washing out joints – Wipe gently to clean tiles without pulling grout completely out of joints.
Change rinse water frequently – Dirty rinse water can leave a film on stone tiles.

Curing and Sealing Grout

Allowing adequate cure time for the grout and applying a quality sealer are important final steps:

Air dry tiles initially – Let tiles sit 30-60 minutes undisturbed after grouting.
Lightly dampen after 1 hour – Use a barely moistened sponge to re-hydrate grout joints.
Allow 24-48 hour cure – Prevent foot traffic or wiping tiles during full grout cure.
Watch for haze – If a slight haze appears, use a grout haze remover made for stone. Test first.
Apply grout sealer – After full cure, seal grout lines with a water-based sealer formulated for stone and grout.
Cure sealer completely – Allow sealer to fully dry per product directions before using backsplash.
Re-seal grout yearly – Regular re-sealing will maintain protection from stains.

Grout Color Considerations

Choosing a grout color requires considering tile color, overall decor, and personal preference:

Match grout to stone – Matching white grout with white marble tiles can provide a seamless look.
Contrasting grout – Charcoal grout highlighted against light travertine tiles can be striking.
Complementary grout – Medium gray grout blends nicely with some types of slate tiles.
Stick with white or gray – These two grout colors work well with nearly any stone tile.
Visit showrooms – View grout color samples next to stone tiles being used to visualize effect.
Test on spare tiles – Try different grout colors on leftover tiles to see overall look.
Consider maintenance – Lighter grout is easier to keep clean long-term.
Personal preference – Choose a grout color that works with your tastes and kitchen or bath style.

Tips for Grouting Stone Tiles

Follow these helpful tips when grouting a stone tile backsplash:

Always test stones like marble or travertine for acid sensitivity before grouting.
Grout stone tiles with unsanded grout only. Sanded grout can scratch soft stones.
Grout joints wider than 1/8-inch may need back-buttering each tile during installation.
Set tiles firmly in place and level to prevent movement during grouting.
When spreading grout, work in small sections of 3-4 square feet at a time.
To create a polished look, “buff” stone tile gently with a cheesecloth once grout has dried.
Change rinse water every few square feet to avoid film build-up on tiles.
Inspect joints for unfilled spots and re-grout before moving onto next section.
For vertical applications like subway tile, grout from top to bottom to prevent dripping.
Allow full 72 hours curing before heavy cleaning of stone tile grout.

Grout Maintenance and Re-Grouting

With proper care, grout on a stone tile backsplash can last for years:

Seal grout annually to maintain stain protection and color evenness.
Use pH-balanced cleaners formulated for stone to regularly clean tiles and grout.
Re-apply grout sealer if grout appears dull, discolored, or is easily stained.
Deep clean grout yearly with a steam cleaner or stiff nylon brush.
Re-grout if joints become excessively cracked, pitted or concave over time.
To re-grout, rake out old grout with a carbide grout saw and re-apply fresh grout.
Consider epoxy or urethane grout for high-moisture areas prone to frequent staining.

Grouting Stone Tile Backsplash FAQs

What’s the best grout to use on a stone tile backsplash?

For most stone tiles, an unsanded grout is best to avoid scratching. Urethane or epoxy grout is also suitable for stone in wet areas. Match grout color to your tiles.

How soon can I grout stone tile after installing?

It’s crucial to allow mortar to cure fully behind tiles, generally 24-48 hours. Grout too soon and tiles may shift out of place.

Should all grout joints be exactly equal thickness?

Some minor variation in grout line thickness is normal. But joints should not exceed 1/8 inch which can lead to cracking.

What causes pitting and cracking in grout joints?

Insufficient initial grouting, inadequate curing time, and lack of sealing are common causes of premature grout deterioration.

Why seal grout on stone tile?

Sealing grout creates a protective barrier that prevents stains from penetrating porous grout and helps grout lines stay clean.

How long does grouting a backsplash take?

Expect grouting a standard 8-foot by 4-foot backsplash to take 2 hours or more, not including drying times. Rushing can ruin the final look.

Can I polish my stone tiles after grouting?

Yes, gently polishing with a cheesecloth or dry microfiber cloth can help bring out the natural shine of stone tiles after grouting.

Conclusion

Grouting a stone tile backsplash adds attractive, finished detailing to your space while protecting tiles and providing years of enjoyment. With unsanded grout, some handy tools, and these tips, you can confidently tackle grouting stone tile yourself. Taking careful precautions during prep, installation, and curing will reward you with a brilliant backsplash you’ll love showing off.