Tiling a backsplash can greatly improve the look and feel of your kitchen, and it’s a DIY project many homeowners decide to take on. However, tiling the inside corner of a backsplash can be tricky for even the most seasoned DIYers. With some planning, the right materials, and proper technique, you can tile your inside corners like a pro.
Choosing Your Tile
The first step in tiling any backsplash is choosing your tile. For inside corners, you’ll want to select a tile that is:
- Small and uniform in size – large or uneven tiles will be difficult to cut and lay evenly in corners. Mosaic tiles, subway tiles, or smaller square tiles are great options.
- Not too thick – Thicker tiles will have a more visible grout line in corners. Opt for thinner tiles around 1/4 inch thick.
- Durable and water-resistant – The inside corner sees more water exposure over a sink or range. Pick a tile that can withstand moisture like ceramic, porcelain, or glass.
Many homeowners choose subway tiles or mosaics for inside corner backsplashes because they easily fit the space and create clean lines. White or neutral colored tiles also give an expanded, seamless look. Add pops of color with your grout.
Gather Your Materials
In addition to your tiles, you’ll need the following supplies:
- Tile adhesive mortar
- Grout
- Grout sealer
- Trowels for spreading mortar
- Tile spacers
- Tile cutter and nippers
- Utility knife
- Tape measure
- Level
- Mixing bucket
- Mixing paddle
- Sponges
- Corner trowel
- Eye protection
For inside corner tiles specifically:
- Bullnose tiles
- Pearlized caulk/silicone sealant
Prepare the Surface
Proper prep work is key to getting tiles to adhere in an inside corner.
- Clean the surface thoroughly – Remove any old backsplash material, debris, grease, or soap scum with a degreaser and rinse well. Let dry fully.
- Repair any damage – Fill holes, chips, and cracks with spackle or caulk and let cure per product directions. Sand smooth.
- Prime if painting – If you plan to paint your backsplash tiles, apply primer before tiling. Let cure fully.
- Apply mortar to test area – Spread a small section of thinset mortar and allow to dry completely. This tests adhesion before tiling the entire space.
Thorough prep removes any barriers between your tile and the surface for best adhesion in an inside corner.
Lay Out Your Tiles
Now comes the fun part – laying out your tiles! Following a few tips will set you up for success:
- Start in the corner – Lay a vertical column of tiles from counter to cabinet in the inside corner first. This gives you a straight line to build off of.
- Use bullnose tiles – Bullnose tiles have a curved finished edge that fits neatly into corners. Install bullnose tiles on the edges that will butt into the corner.
- Cut narrow border tiles – Any tiles that border the corner will need to be cut narrow so they don’t overlap the bullnose edges. Leave a 1/16″ gap between the bullnose and flat tiles.
- Use spacers – Place tile spacers between each tile to get straight grout lines. Remove spacers before grouting.
- Check levels often – Use a level frequently to ensure your tiles remain straight. Make minor adjustments if they start to skew.
- Dry fit first – Lay tiles without mortar to perfect the layout before permanently setting.
Once your corner tiles are laid, continue building out rows. Refer to the rest of the wall and countertop to keep everything aligned.
Mix and Apply the Mortar
Mixing the mortar well and applying it correctly ensures your tiles adhere properly in the corner:
- Mix per package directions – Don’t guess! Follow the mixing ratios and directions on your thinset bag.
- Allow proper slake time – Let the mortar sit after mixing for the recommended slake time so ingredients activate. This makes the mortar sticky.
- Use the proper trowel – Choose a notched trowel size based on your tile to achieve full mortar coverage on the backs.
- Spread evenly in sections – Cover only a small section of the wall at a time so the mortar doesn’t dry out.
- Apply mortar to back of tiles – In addition to the wall, putting a skim coat of mortar on tile backs provides maximum adhesion.
- Set tiles firmly – Press tiles into the mortar with a slight back and forth motion until the mortar comes out the sides evenly.
Take your time applying mortar for super strong bonds, especially in the corner.
Grouting Seams
Once the thinset cures per the product directions, you’re ready to grout. Grouting seals the tiles together and prevents moisture issues in an inside corner.
- Prepare precision tools – Have a corner trowel, nippers, and artists brush ready to grout the corner seam.
- Mix grout – Prepare grout per package instructions. Let sit for the recommended slake time before applying.
- Apply grout – Holding the trowel at a 45° angle, spread grout diagonally across the tiles to fill the joints.
- Pack corner tightly – Use the corner trowel to tightly pack grout into the corner seam. Remove excess.
- Smooth with corner tool – Shape and profile the corner grout with the curved corner trowel for a neat finish.
- Clean grout haze – Wipe a damp sponge diagonally across tiles to clean off haze and shape joints. Rinse sponge frequently.
- Seal grout – Once dry, apply grout sealer to protect from moisture and stains, especially in the hardworking corner.
Take care to fully pack the inside corner grout line and wipe it smooth. Well-grouted corners prevent cracks and provide a polished finish.
Finish with Caulk
As a final step to cleanly finish the intersection between your countertop and backsplash tiles:
- Clean the gap – Remove any old caulk, grout, or debris between the countertop and tiles with a utility knife. Wipe clean.
- Apply painter’s tape – Place strips of painter’s tape along the counter and tile edges to create clean caulk lines.
- Run a bead of silicone – Run a steady, narrow bead of 100% silicone caulk along the gap. Smooth with a fingertip.
- Remove tape – Carefully remove painter’s tape before the caulk dries.
- Wipe corner clean – Use a damp paper towel or sponge to immediately wipe up any stray caulk and shape the corner.
The flexible silicone prevents cracking in the natural expansion joint between countertops and tile backsplashes. This gives your inside corner a flawless look.
And that’s it – you have successfully tiled an inside corner backsplash! With the right prep, materials, and elbow grease, you can tackle this tricky task. Keep your new backsplash looking like new by using gentle cleaners, resealing grout annually, and watching for any loose or cracked tiles in your high traffic corners. Enjoy your updated, beautiful kitchen!
Frequently Asked Questions About Tiling Inside Corner Backsplashes
Many homeowners have additional questions when it comes to tiling the inside corner of their backsplashes. Here are answers to some of the most common FAQs:
Should I use whole tiles or cut tiles in the corner?
It’s best practice to use a full bullnose tile on the edges that butt into the corner rather than trying to cut traditional flat tiles to fit. Bullnose tiles have a rounded finished edge made for inside corners. Cut only the bordering tiles that nestle next to the bullnose tiles.
What’s the best way to cut tiles for an inside corner?
Use a wet saw fitted with a diamond tile blade to precisely cut border tiles to fit around bullnose tiles. Mark your cut lines with a pencil and ruler, and cut slowly and steadily for clean edges. Use nippers to nip small precision pieces as needed to fit together like a puzzle.
Can I use premixed mastic instead of mixing thinset mortar?
Premixed mastics don’t gain the strength needed for tiles to adhere well on inside corners. Using a polymer-modified thinset mortar is best. It creates a much stronger bond, preventing tiles from cracking or popping off the corner.
How long should I let the thinset mortar dry before grouting?
It’s extremely important to allow the mortar to cure fully – usually 24-48 hours. Check the mortar packaging. If you grout too soon, the grout can pull the tiles off the wall when it shrinks as it cures. Patience pays off.
Should I use sanded or unsanded grout for an inside corner?
Sanded grout stands up better to moisture and traffic. But it can scratch polished or glass tiles. Use unsanded grout for glass, marble, or other delicate tile, and sanded for ceramic, porcelain, or natural stone. Either way, sealing the grout is a must.
How do I keep the inside corner caulk bead straight when applying?
Painter’s tape is a game changer for applying straight caulk lines. Run tape strips along both sides of the corner gap before caulking for perfectly straight edges. Remove tape immediately after smoothing the bead with your finger before it dries.
Conclusion
Tiling the inside corners of a backsplash provides a polished finish but requires careful planning and execution. With the right materials, proper surface prep, strategic tile layout, meticulous mortar application, and sealing the grout lines, you can achieve seamless, professional-looking results. Focusing on each step and not rushing the drying times leads to success. If at any point the process seems daunting, don’t hesitate to call in a tile installation pro. An expert can bail you out of any sticky situations in the tricky corners. But with a steady hand and attention to detail, you can handle tiling your inside corner backsplash like a true pro.