What Size Trowel for Backsplash – A Complete Guide

Installing a backsplash in your kitchen or bathroom can dramatically transform the look and feel of the space. But getting those backsplash tiles set properly requires the right trowel. Choosing the right size trowel for your backsplash is key to achieving a professional result. This comprehensive guide covers everything you need to know about selecting the proper trowel size for your backsplash installation.

Introduction to Trowels

A trowel is a hand tool used by tile setters to apply and spread adhesive or mortar onto surfaces in preparation for setting tiles. Trowels consist of a flat metal blade with a handle. The shape and size of the trowel blade makes a major difference in how the adhesive is applied.

Using the right size trowel helps ensure:

  • Proper coverage of the setting material
  • Desired thickness of the adhesive layer
  • Optimal adhesion of the tiles

Choosing a trowel with the proper blade dimensions allows you to achieve full contact between the back of the tiles and the adhesive. The more complete the contact, the better the tiles are bonded.

Trowel Sizes for Backsplashes

Trowel sizes are categorized by the shape and dimensions of the blade. For backsplash installations, you generally need a trowel with a square-notched blade.

The most common trowel sizes used are:

  • 1/4″ x 1/4″ x 1/4″ square notch
  • 1/4″ x 3/8″ x 1/4″ square notch
  • 1/2″ x 1/2″ x 1/2″ square notch

The numbers refer to the width, depth and spacing between the notches.

Trowel with square notched blade
  • A 1/4″ x 1/4″ x 1/4″ trowel creates adhesive lines 1/4″ wide, 1/4″ deep, and 1/4″ apart
  • A 1/4″ x 3/8″ x 1/4″ trowel makes ridges 1/4″ across, 3/8″ deep, spaced 1/4″ apart
  • The 1/2″ x 1/2″ x 1/2″ trowel produces 1/2″ wide adhesive lines with 1/2″ depth and spacing

The bigger the square notches, the more adhesive the trowel holds and applies.

Factors That Determine Trowel Size

Choosing the ideal trowel for your backsplash depends on several factors:

Tile Size

  • Smaller mosaic tiles – 1/4″ square notch trowel
  • Medium tile sizes up to 4”x4” – 1/4”x 3/8” trowel
  • Larger format tiles 6”x6” and bigger – 1/2″ square notch

Match the trowel size to the tile dimensions for optimal coverage. The trowel ridges should run perpendicular to the tile edges.

Tile Type

Rough, irregular surfaces on tile backs require more adhesive.

  • Smooth backed glass, ceramic and porcelain tiles – smaller trowel size
  • Textured surfaces like handmade, tumbled or pebble tiles – larger trowel

Enough adhesive must fill the grooves and contours on textured tile surfaces.

Adhesive Type

Some adhesives are formulated thicker than others.

  • Thin-set adhesives allow use of smaller trowels
  • Medium bed adhesive requires larger notched trowels
  • Mortar is applied with the largest square notched trowel

Consult the adhesive packaging to determine the proper trowel size.

Surface Flatness

Level, smooth substrates can utilise smaller trowels. Uneven surfaces need deeper adhesive layers to fill the voids, necessitating larger trowels.

  • Flat drywall or cement backerboard – 1/4″ trowel often sufficient
  • Uneven masonry or concrete surfaces – larger 3/8” or 1/2″ trowel to fill unevenness

Test the surface first to see if any high and low spots need filling with thicker adhesive.

How to Choose Trowel Size

Follow these guidelines to select the appropriate trowel size for your backsplash:

  • Consult the tile and adhesive manufacturers’ recommendations. The products’ packaging and documents often specify appropriate trowel size.
  • Consider the factors – tile type and size, adhesive thickness, and substrate contours.
  • Look at the tile backs. Measure depth of depressions, grooves or texture.
  • Use a trowel where the ridges are slightly wider than surface irregularities to allow filling.
  • Ensure ridges will align perpendicular to backsplash tile edges.
  • For mosaics under 2” size, use 1/4″ square notch trowel.
  • For smooth surface tile 4”x4” or smaller, start with 1/4″x 3/8” trowel.
  • Textured natural stone tiles may require 1/2″ square notch trowel.

Test a few tiles with the trowel you select. There should be full adhesive contact over entire tile back with no voids. Adjust trowel size as needed to maximize coverage.

How to Use the Trowel

Once you’ve selected the proper trowel for your backsplash, here are some tips for putting it to use:

  • Angle the trowel 45 degrees to the surface and spread a thin layer of adhesive.
  • Apply more adhesive and use the trowel ridges perpendicular across the entire area.
  • Firmly press tiles into the adhesive ridges with a slight back and forth motion.
  • Use the flat side of the trowel to flatten ridges for thinner adhesive layers as needed.
  • Periodically remove built-up adhesive from the trowel blade edges.
  • Discard worn trowels with rounded, smooth edges that prevent proper adhesive application.

Take care not to spread more adhesive than can be tiled over within the working time. Work in sections if needed.

Trowel Options

Trowels come in a variety of materials and handle types.

Blade Materials

  • Stainless steel – most common, durable, easy to clean with long life
  • Carbon steel – slightly less expensive but rusts more easily
  • Plastic – economic option but less rigid, can flex during use
  • Notched flooring trowels – designed for tile floors, often too large for backsplashes

Stainless steel is the best choice for backsplash tiling.

Handle Types

  • Classic wood handle – traditional, good grip, more expensive
  • Soft grip handle – plastic or rubberized, comfortable, reduces hand fatigue
  • Cushion grip – softer feel, relieves stress on fingers and hands
  • Ergonomic – contoured shape fits hand anatomy, prevents strain

Consider your budget, comfort, and ease of use when selecting a trowel handle type.

Purchasing a Trowel

You can find trowels at most hardware stores, home improvement centers, tile shops, and online. Purchase a high-quality trowel made for tile setting.

What to look for when buying a trowel:

  • Stainless steel blade for durability and longevity
  • Comfortable handle to reduce hand and finger tiredness
  • Square notched blades sized for backsplash tiling
  • Width to match your tile dimensions
  • Depth to fill adhesive needs of tile backs
  • Certified precision ground and polished blade for smooth finishes
  • Reputable tool brand known for quality and performance

Avoid cheap trowels that can bend, warp out of shape, pit, or corrode. This can affect adhesive application. Investing in a high grade trowel will reward you with easier, faster tiling and better backsplash results.

Maintaining Your Tile Trowel

To maximize the working life of your backsplash trowel:

  • Clean after every use – wipe off adhesive before it dries using a putty knife and damp cloth or sponge. Avoid abrasives.
  • Dry thoroughly after cleaning.
  • Apply a thin coating of oil to prevent rust if your trowel isn’t stainless steel. Wipe off any excess.
  • Store in a dry location.
  • Inspect for wear and replace as needed. Dented, bent or worn trowels should not be used.

A well-cared for trowel can deliver years of smooth adhesive application for numerous tiling projects.

Common Backsplash Trowel Questions

What size trowel for subway tile backsplash?

For standard 3×6 inch subway tiles, a 1/4″ x 3/8″ square notch trowel is recommended. The 3/8″ deep notches provide sufficient adhesive for the smooth tile backs.

What size trowel for large format backsplash tile?

For tiles 8″ x 8″ and larger, use a 1/2″ x 1/2″ square notch trowel to ensure proper coverage on the backs of the large tiles.

Can I use a wall tile trowel for backsplash?

Wall tile trowels are suitable for backsplash installation. They have smaller notched dimensions designed for thinner adhesive application on walls versus floors.

What size trowel for glass backsplash?

Since glass tiles have smooth finished backs, a 1/4″ x 1/4″ square notch trowel is usually adequate for glass mosaic backsplash projects.

For marble or natural stone backsplash tile, is a larger trowel needed?

Polished marble, travertine, and other natural stone tiles benefit from a larger 3/8″ or 1/2″ square notch trowel to allow adhesive to fill the depressions and undulations on the back surface.

Trowel Size Recommendations by Tile Type

Here are the generally recommended trowel sizes for common backsplash tile materials:

  • Glass tile mosaics – 1/4″ square notch
  • Ceramic mosaic tiles – 1/4″ square notch
  • Porcelain mosaic tiles – 1/4″ x 3/8″ square notch
  • Subway tile 3×6” or 4×4″ – 1/4″ x 3/8″ square notch
  • 6×6″ ceramic or porcelain tile – 1/4″ x 3/8″ square notch
  • 8×8″ ceramic, porcelain or stone tiles – 1/2″ square notch
  • Stone mosaics – 1/2″ square notch
  • Large format ceramic or porcelain tiles – 1/2″ square notch
  • Natural stone tiles – 1/2″ square notch

Always refer to manufacturer recommendations and test tiles first. Adjust trowel size up or down as needed.

Troubleshooting Trowel Size Issues

Problem: Tiles are loose, lack adhesion, or pop off.

Solution: Use a larger trowel size to increase adhesive depth for better contact.

Problem: Too much adhesive is squeezed out between tiles.

Solution: Switch to a smaller notch trowel so adhesive layer is thinner.

Problem: Adhesive application is uneven with poor coverage.

Solution: Trowel blade may be worn out. Replace old trowel with a new one.

Problem: Adhesive skins over too quickly before tiles can be set.

Solution: Use a thinner layer of adhesive with a smaller trowel. Work in smaller sections.

Key Takeaways

  • Selecting the proper trowel size is vital for successful backsplash installation.
  • Consider tile size, tile type, adhesive properties, and substrate contour.
  • Size the trowel notches to fit grooves and textures on the tile backs.
  • Angle the trowel 45 degrees and apply adhesive using perpendicular strokes.
  • A high quality stainless steel trowel prevents adhesive application problems.
  • Maintain the trowel blade to maximize its working life.

Choosing and using the right size trowel makes backsplashes quicker to tile and easier to install perfectly. Arm yourself with the proper trowel and spread on beautiful backsplash results.

Frequently Asked Questions About Trowel Size for Backsplash

What size trowel do I need for a kitchen backsplash?

For a kitchen backsplash, a 1/4″ x 3/8″ square notch trowel is recommended. This size works well for common 4 x 4 inch ceramic subway tiles or smaller mosaics. The 3/8″ deep notches allow you to achieve full adhesive contact on the tile backs.

Can I use the same trowel for the backsplash and floor?

It’s best to have separate trowels for floor and wall tile projects. Floor trowels are larger to provide thicker adhesive beds. Using a large flooring trowel on backsplash tiles can result in too much adhesive and tiles sliding out of position.

What happens if the trowel size is too small?

If the trowel size is too small, it applies a thinner layer of adhesive. This can prevent full contact between the tile backs and substrate. Gaps in adhesive can allow tiles to loosen or fall off over time.

What do I do if the tile slides after placing?

If placed tiles slide around, it means too much adhesive was applied. Try a smaller square notch trowel to reduce the depth and amount of adhesive. The thinner application will prevent excess slipperiness while still adhering tiles properly.

Can I use a grout float for backsplash instead of a trowel?

Grout floats are designed for applying grout not adhesive. The sponge surface does not provide the right ridge pattern for even adhesive distribution. Always use a proper rigid steel trowel for backsplash tile installation.

How do I clean adhesive off my trowel?

Regularly remove buildup by scraping off adhesive with the tile edge while it’s still wet. After use, soak the trowel in warm soapy water then wipe clean with a sponge or rag before it dries. Avoid using solvents or abrasives as this damages the blade.

When should I replace my trowel?

Look for worn down notches, pitting, rust spots, dents or bends in the blade. Any deformation prevents the trowel from creating consistent, even adhesive ridges. Trowels should be replaced every 1-2 years depending on use.

What is the best trowel brand for backsplashes?

Top trowel manufacturers include Marshalltown, Raimondi, Bon, Mapei, Montolit, and Rubi. Look for precision ground stainless steel blades with comfortable cushion grip handles. Avoid cheap unbranded trowels that lose shape and wear out quickly.


Determining the proper trowel size makes achieving a flawless backsplash much simpler. With the right square notched trowel that matches your tile size, backsplash installation becomes much easier. Just apply the adhesive perpendicular to the tile edges, set them in place, and enjoy your attractive new backsplash.

Armed with the guidelines provided in this article, you can confidently choose an appropriate trowel and expertly install beautiful backsplash tile the easy way.