How to Install a River Rock Backsplash

A river rock backsplash can be a gorgeous addition to any kitchen or bathroom. The smooth, rounded shapes and multi-colored patterns of river rocks create a natural, earthy look that is warm and inviting. Installing a river rock backsplash is a relatively easy DIY project that can completely transform the look of a space. With some basic tools, materials, and these step-by-step instructions, you’ll have a beautiful new river rock backsplash in your home in no time.

Benefits of a River Rock Backsplash

There are many great reasons to consider installing a river rock backsplash in your home:

  • Visual Appeal – The organic shapes, varied colors, and textures of river rocks create a stunning visual focal point in any space. River rock backsplashes blend beautifully in rustic, farmhouse, or nature-inspired decors.
  • Durability – River rocks are naturally strong and durable. Unlike tile or other delicate materials, a river rock backsplash can withstand hits, scratches, and daily wear-and-tear.
  • Easy Maintenance – There are no grout lines to scour or seal with a river rock backsplash. Simply wipe down the rocks occasionally with a damp cloth to keep them looking great.
  • Affordability – Loose river rocks are an budget-friendly backsplash material. You can often find river rock sold in bulk for a few dollars per pound.
  • Creativity – River rock backsplashes allow for creativity in the design. You can create whatever shape or pattern you desire by carefully arranging the rocks.

Choosing River Rocks

The first step in installing a river rock backsplash is selecting the right rocks. Here are some useful tips for choosing river rocks:

Rock Shape

  • Tumbled river rocks – These are naturally smooth and rounded rocks that have been tumbled to further smooth any rough edges. Tumbled rocks create a relaxed, organic look.
  • Irregular river rocks – These jagged, uneven rocks create a more rugged, natural stone appearance. They come in varied shapes and sizes.
  • Flat river rocks – As the name implies, these rocks have a flatter profile and can be stacked closely together. They create a smoother overall look.

Rock Size

  • Small 1-2 inch rocks are best for a more refined, uniform look.
  • Medium 2-3 inch rocks add more drama and dimensionality.
  • Large 3-5 inch rocks create a bold, chunky statement.

Rock Color

  • Neutral river rocks in grays, taupes, and beiges are versatile and easy to match with any decor.
  • Multi-colored rocks with various natural shades add striking visual interest.
  • Painted river rocks offer even more color options, like bold reds or ocean blues.

Estimating How Much River Rock You Need

Once you’ve chosen the ideal rocks, it’s important to purchase the right amount. Measure the total square footage of the backsplash area and use these estimates:

  • For small 1-2″ rocks, you’ll need about 5 pounds per square foot.
  • For medium 2-3″ rocks, 3 pounds per square foot.
  • For larger 3-5″ rocks, 2 pounds per square foot.

It’s always smart to buy 10-20% more than calculated to allow for error and customizing the design. You can return any unused rocks.

Gather Supplies

In addition to the river rocks, gather these supplies before starting:

  • Grout or thinset mortar
  • Grout sealer
  • Trowel for applying mortar
  • Bucket or wheelbarrow for mixing mortar
  • Foam float or small trowel for spreading grout
  • Grout sponge
  • Rags
  • Painter’s tape
  • Caulk and caulk gun

Safety gear like gloves, safety glasses, a mask, and knee pads is also recommended.

Prepare the Surface

Proper surface prep is crucial for a long-lasting river rock backsplash. Follow these tips:

  • Remove any old backsplash completely. Scrape off all leftover adhesive.
  • Thoroughly clean the area using a degreasing cleaner to eliminate dirt, oil, and soap scum.
  • Fill any holes, chips, or cracks with drywall compound or spackle for a smooth surface.
  • Lightly roughen glossy surfaces like tile for better adhesion.
  • Trim any uneven edges to ensure the backsplash will lay flat.
  • Carefully cut out areas behind receptors, outlets, etc. to fit rocks.
  • Use painter’s tape to mask off any adjacent surfaces to keep clean.

Apply the Mortar

With a perfectly prepped surface, you’re ready to apply the mortar that adheres the rocks. Follow these application tips:

Choose the Right Mortar

  • For walls, use non-sanded thinset mortar which is specially designed for stones and tiles.
  • For floors, use a thicker sanded floor mortar to support weight.

Mix the Mortar

  • Mix powered thinset mortar with water per package directions, until a wet, slippery consistency.
  • Only mix what you can use in 30 minutes to avoid drying.

Spread the Mortar

  • Use the notched edge of a trowel held at a 45° angle to spread on a thin, uniform layer of mortar.
  • Apply it in small sections so the mortar doesn’t dry before adding rocks.
  • Make sure the layer is just deep enough to adhere the rocks, about 1⁄4-1⁄2 inch.

Arrange the River Rocks

Now for the fun and creative part – arranging the rocks on the mortar! Follow these tips:

  • Work in sections for easier installation and to ensure the mortar stays tacky.
  • Create your desired design, mixing rock sizes and colors. Organic, random patterns work beautifully.
  • Heavier rocks can be placed first, then fill in gaps with smaller rocks.
  • Place rocks very close together, barely touching or with small grout lines if desired.
  • Each rock should be embedded halfway into the mortar. Press gently but firmly.
  • Strike rocks with a rubber mallet to further embed larger or uneven ones.
  • Use shims or spacers between rocks if needed to keep layout consistent. Remove after mortar dries.
  • Clean away excess mortar immediately with a damp cloth. Take care not to smear.

Apply Grout

Once the rocks are fully adhered, grouting is an important step to complete the backsplash. Follow these tips:

Grout Options

  • Unsanded grout is best for thin, 1/8″ grout lines like with river rock backsplashes. Avoid sanded grout.
  • Standard gray or off-white grout matches most river rock colors. Or choose an earthy brown, tan, or umber.

Mix and Apply Grout

  • Mix a batch of grout per package instructions to a thick, peanut butter-like consistency.
  • Holding a grout float or small trowel at a 45° angle, firmly press grout into all rock joints and gaps.
  • Remove excess immediately and clean the rock faces with a damp grout sponge.
  • Buff off a light grout haze with cheesecloth once dried for shiny rocks.

Seal the Grout

  • After a full cure of 1-2 weeks, seal the grout lines with a penetrating grout sealer.
  • Follow product directions, applying carefully just to the grout and wiping any excess from rock surfaces.

Finish With Caulk

The final step is applying color-matched caulk to “finish” the backsplash installation:

  • Run a smooth, continuous caulk bead along all joints – where the rocks meet countertops, walls, ceilings, or any edges.
  • Dampen a finger and gently smooth and shape the caulk into a neat shape. Wipe away excess.
  • Allow the caulk to fully cure for 24-48 hours before exposing it to water.

And that’s it – you now have a complete and stunning river rock backsplash! Proper prep, mortar application, careful rock installation, grouting, and caulking are the keys to success. Take care of your new backsplash and it will add natural beauty to your space for years.

Frequently Asked Questions About River Rock Backsplashes

What type of rock is best for a backsplash?

Tumbled river rocks typically work best. Their smooth, rounded shape allows for tight placement and small grout lines. Plus, they are comfortable underfoot for floor installations. Jagged irregular rocks can also be used but may require wider grout lines.

How do I cut river rocks?

It’s best to avoid cutting river rocks which can split or shatter them. Instead, arrange whole rocks to fit around any edges or obstacles. Or use small pebbles or chipped rock fragments to fill smaller gaps. If cutting is absolutely necessary, a wet saw with a diamond blade can be used very cautiously.

Should I seal my river rock backsplash?

Sealing is an optional extra step that can help protect the rocks from stains and water absorption. Use a food-safe sealer made for natural stone. Multiple thin coats work better than one thick coat for maximum penetration and protection. Re-apply yearly.

What color grout should I choose?

Always match the grout color to your rocks. Standard gray is suitable for most multi-colored river rocks. Choose a brown, tan, or umber grout for warm-colored stones. White and off-white work well for neutral and icy blue-gray rocks. Avoid high-contrast black and darker grouts.

How do I clean and care for a river rock backsplash?

River rock backsplashes are easy to maintain with just simple cleaning as needed. Gently wipe down the rocks using a mild dish soap and warm water. Avoid harsh cleaners which can strip the sealant. Re-seal rocks every 1-2 years for optimal stain resistance and water repellency.

Can I install a river rock backsplash over existing tile?

Yes, river rocks can be installed over existing backsplash tile. Thoroughly clean and scuff sand the old tile to improve adhesion before applying the mortar and rocks. Check that the tiles are well-adhered – replace any loose ones to ensure a smooth, secure surface for the rocks.

What’s the best adhesive for securing river rocks?

Thinset mortar specifically formulated for stones and tiles is ideal. It provides a strong permanent bond. Organic mastics and construction adhesives don’t offer the same bonding strength. Always apply a primer coat first on slick surfaces like metal or glass.

How do I arrange irregularly shaped rocks?

Irregular rocks can create a more challenging layout, like assembling a puzzle. Start by grouping rocks of similar sizes, shapes and colors. Loosen tight clusters by inserting complementary rocks in the gaps. Aim for an organic design that balances uniformity of color with interesting variety in shapes and textures.

Can I install a river rock backsplash outside?

Yes, river rocks are a great choice for an outdoor backsplash behind a grill or around a pool, for example. Be sure to use exterior-rated thinset mortar and grout designed for freeze-thaw durability. Allow proper cure time before prolonged water exposure. Re-sealing yearly is also crucial for outdoor installations.


Installing a river rock backsplash brings the relaxed beauty of nature into any space. With an array of rock shapes, sizes, and colors to choose from, you can create a completely custom look that matches your unique style. Once in place, a river rock backsplash is easy to care for and will provide lasting durability and visual delight for years to come. Just be sure to use the proper mortar, grout, and installation techniques outlined here to achieve success. Let your imagination run wild designing a river rock statement wall that becomes the gorgeous focal point of any room!