How to Apply Unsanded Grout to Backsplash

Applying unsanded grout to a backsplash can seem daunting, but with the right tools and techniques, it can be a straightforward DIY project. Unsanded grout is ideal for narrow joints between backsplash tiles that are less than 1/8 inch wide. The fine consistency allows it to fully pack the joints for a smooth finish. Follow this step-by-step guide for tips on how to properly apply unsanded grout to your backsplash.

What You’ll Need

  • Unsanded grout
  • Grout float
  • Grout sponge
  • Grout sealer (optional)
  • Bucket or mixing tray
  • Rubber grout float
  • Clean water
  • Mixing stick
  • Cloth rags
  • Painter’s tape

Preparing the Tiles

Before applying the grout, make sure the tiles are clean and that all spacers have been removed from the joints. Use a damp sponge to wipe away any dust or debris. It can also help to go over the tiles with a slightly damp towel and then buff dry. This will remove any remaining residue and help prevent the grout from staining the tiles.

Apply painter’s tape along the countertop edge above the backsplash. This will make clean up easier and prevent the grout from staining the countertop. It’s also a good idea to cover any adjacent surfaces, such as the wall or cabinets, with plastic sheeting or rosin paper to protect them from splatters.

Mixing the Grout

Always refer to the manufacturer’s instructions for exact mixing directions. In general, you’ll want to add powdered grout to clean water in a bucket or mixing tray, using approximately 3 parts powder to 1 part water. The mixture should be the consistency of thick peanut butter. Use a mixing stick to thoroughly blend.

Only mix up as much grout as you can use in about 30 minutes. Unsanded grout starts to harden once mixed with water. Don’t try to re-temper batches by adding more water, as this will weaken the grout.

Applying the Grout

There are several techniques for applying grout:

Push Method

Hold the rubber grout float at a 45 degree angle and force the grout diagonally into the joints using a sweeping motion. Apply even pressure and completely pack the joints full.

Spread Method

Use the rubber grout float like a squeegee, dragging it at a 45 degree angle across the tiles to apply the grout. Keep an even layer across the surface and work in small sections.

Finger Application

Simply use your fingers or a sponge to force the grout into the joints. This works well for smaller jobs. Just be sure to pack the joints fully.

Whichever technique you use, make sure to completely fill the joints and remove any excess from the tile surface as you work. Periodically remove any grout that gets on the tile face with a damp sponge. Don’t let it dry or it could stain.

Cleaning and Finishing the Grout

Once all the joints are filled, wait about 15 minutes for the grout to firm up slightly. Then go over the entire surface with a damp grout sponge, using a circular motion to smooth and level the joints. Rinse the sponge frequently in a bucket of clean water.

Continue cleaning until you’ve removed any haze and the grout joints are uniform. Use as little water as possible to avoid pulling too much grout back out of the joints. Allow the grout to dry for 24-48 hours.

Once completely dry, you can polish the grout with a soft, dry cloth to further smooth the joints. Apply a penetrating grout sealer as an optional final step to protect the grout from stains. Carefully follow the product directions.

And that’s it! With a little time and patience, you can achieve smooth, uniform grout lines on your backsplash. Taking care to properly prepare, apply, and clean the grout will help ensure it cures evenly for a professional finished look.

Frequently Asked Questions

What is the best grout float to use?

A grout float made of soft rubber is ideal. It allows you to apply pressure evenly and pack the joints completely. Metal or hard plastic floats could scratch some tile surfaces.

How soon can I clean the grouted area?

It’s best to wait about 10-15 minutes for the grout to firm up before cleaning. This prevents pulling too much material back out of the joints.

Why is my grout cracking after it dried?

This usually occurs due to improper mixing or drying too quickly. Always follow manufacturer’s mixing directions and allow proper cure times.

What’s the best way to apply grout to the vertical joints?

Use the push method and apply pressure from top to bottom. You can also grout horizontal joints first to create a base.

How do I get all the grout lines even with no low spots?

Frequently change your water when cleaning and smooth with consistent, circular motions. Check for low spots just before the final rinse.


Applying unsanded grout to a backsplash is a satisfying DIY project that can give your kitchen a fresh new look. With some careful prep and the right techniques, you can achieve clean, uniform grout lines. Be sure to fully pack the joints, smoothly clean the surface, and allow proper drying time for best results. Following the steps in this guide will help ensure your backsplash looks professionally finished.