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Tiling 101: Notched Trowels and Their Uses

Estimated Reading Time: 5 min

When laying tile, your choice in notch shape and size can be the difference between loose tiles or a perfectly level, long lasting finish.

No matter the type of tile you’re using – from the smallest mosaic and subway tile to the largest natural stone tiles – notched tile trowels are essential tools for setting them in place. They scoop thin-set, a cement-based mortar adhesive, and spread it over floors and walls, or wherever you’re laying tile. The distinctive notches on the sides of the trowel provide those tiles with an even base of ridged mortar that, when you place your tile down, compresses to provide a complete bond to keep them in place over the years.

But when it comes to picking a Notched Trowel, how do you know which is the right one for the job? Do you need different Notched Trowels for walls vs. floors?

This guide walks you through the crucial differences between and the ideal uses for the 5 most common notch shapes.

  1. V-Notch
  2. Flat V-Notch
  3. Square/U-Notch
  4. Slant Notch
  5. Elliptical, or Deep U-Notch

But first, lets go over some tiling basics.

Tiling Basics: Proper Thin-set Mortar Coverage

Tiling professionals know that proper thin-set coverage is crucial for a successful tile installation. The goal is to have enough thin-set to fully support the tile without having it squishing out of the grout joints since this can create a headache-inducing mess.

Thankfully, the CTEF (Ceramic Tile Education Foundation) has provided thin-set coverage guidelines. They suggest that the minimum mortar coverage should be 80% in dry areas and 95% in wet (showers) or exterior areas. Natural stone tile installations also require 95% coverage in all applications.

How to Check for and Achieve Proper Thinset Coverage

Step 1: Spread Thin-set on Prepared Surface.

Always hold your Notched Trowel at a 45-degree angle to create proper ridges. Notches should flow in the same direction.

Step 2: Place Tile

Place the tile as you would to begin any tile installation, allowing it to collapse and settle into the thin-set.

Step 3: Lift Tile and Check Coverage

Once settled, carefully lift the tile by gripping the corners to check the underside. The corners and edges of your tile should be fully covered in order to have proper support. The interior portion of the tile can have bare spots, but not too many.

Q: What do I do if I don't have proper thin-set coverage?

A: If you find that you have too much or insignificant coverage, adjust your troweling style, notch shape, or notch size appropriately to alleviate these issues. You can also opt to back butter the tile to achieve proper coverage. To do this, spread thin-set on your substrate as described in Step 1, then do the same on the back of your tile. Continue to Step 2 and so on.

Step 4: Begin Installation 

Begin your installation once you've found the notch shape and size appropriate for your project.

V-Notched Trowels

V-shaped Notched Trowel Use a V Notched Trowel for glass mosaic tiles

The V-Notched Trowel is the best Notched Trowel for installing small wall tiles like mosaic backsplashes, detail tile work, and any lightweight glass or ceramic tiles up to 6 square inches.

Its sawtooth pattern blade does a great job of leaving just the right amount of thin-set on your work surface so you can avoid over-smearing large amounts of material, which leads to excess thin-set squeezing through the joints between your tiles. If this happens, it can make for a messy, unstable, and uneven tile installation.

Flat V-Notched Trowels

Flat V Notched Trowel Use a Flat V Notched Trowel for natural stone mosaic tile

Like V-Notched Trowels, the Flat V-Notched Trowel is the preferred choice for wall tile applications; however, the Flat V-shape allows you to put down a little more thin-set than the standard V-shape.

This extra bit of adhesive gives you more grip to apply heavier small tiles, like natural stone mosaics or glazed ceramic tiles up to 6 square inches.

Square Notched Trowels and U-Notched Trowels

Square and U-shaped Notched Trowels Use a square or U shaped notched trowel to install tiles up to 16 inches square

Square Notched Trowels and U-Notched Trowels are the most common notch shape used in tile setting due to their wide range of notch sizes and their subsequent versatility for use with most wall and floor tiles up to 16 square inches (including metal tiles, porcelain, ceramic, larger mosaic meshes, or natural stone and cement tiles).

Both shapes create neat rows of ridges with valleys in between them. So, when a tile is carefully set into place, these ridges flatten out and fill the valleys, providing an even coverage to the backside of your tile for a stronger, more complete bond to your wall or floor.

Pro Tip

For an even stronger, longer lasting bond, you should backbutter your tile before setting them in place. All you have to do is scoop a bit of thin-set with your trowel and “butter” the back of your tile with the trowel’s flat edge until there’s an even, thin spread of thin-set. Simple as that!

The biggest difference between these two shapes are the ridges left behind.

Square Notched Trowels create rows of ridges with a flat top, while U-Notched Trowels form rounded ridges. The "collapsable action," or how the ridges collapse to form a bond between tile and substrate, of these notch shapes are virtually indistinguishable from one another. This means that you will get similar mortar coverage and bond strength no matter which shape you choose. Many professionals will swear by one or the other, but it boils down to preference.

If you’re unsure which shape you should commit to, check the label on the back of your chosen tile or thin-set. Most manufacturers will specify on their label whether you should use a Square or U-Notched Trowel to place their tiles.

Slant Notched Trowels

 Slant Notched Trowelexample of slant notch tile application

Slant Notched Trowels, like the MARSHALLTOWN LayFlat™ Notched Trowel, create unique, wave-like ridges that are already partially collapsed. This promotes better air evacuation to make laying thin medium to large format porcelain tiles even easier since installers won't have to work as hard to achieve proper thin-set coverage. Slant Notched Trowels can be used for floor and some wall tile applications.

Elliptical Notched Trowels

Elliptical or Deep U-shaped Notched Trowel Use an elliptical notched trowel only for heavy large format floor tile

The Elliptical or Deep U Notched Trowel disperses the most thin-set out of all notch shape options. These deep rounded, U-shaped ridges and flat valleys are essential for laying heavy, massive slabs of natural stone, such as marble or granite.

Because of the size and weight of these tiles, this notch shape should only be used for floor tile installations. 

Why Notch Shape and Size Matter When Tiling

Most tile manufacturers will have both notch shape and size recommendations written on the box, and there’s a good reason for why it’s there. Having the right notch shape and size:

Gives you control over how much adhesive you apply

  • Choosing the right notch shape for your tile can prevent over-smearing, which can make your tile application weak and messy.
  • Larger, heavier tiles need notches that leave behind a good amount of thin-set so they have something to stick to.
  • Smaller lightweight tiles do not need as much thin-set for a long lasting result.

Keeps your tiles in place longer

  • Pros know that as your tile size and weight increases, so should your notch shape and size.

Helps you avoid a bad installation

  • If you used a V-Notched Trowel to install heavy 8” x 8” tiles on your walls, you wouldn’t have enough adhesive left on your surface to hold up the tiles’ weight and they may come shattering to the ground.
  • The reverse is true for smaller tiles; too much thin-set on your surface makes walls and floors look bumpy and the edges of the tiles may come loose.

Conclusion

Whether you’re installing ceramic, porcelain, or natural stone tiles like slate and marble, all you need is a bit of thin-set and the right notched trowel to finish your tiling project for long lasting and professional DIY results.

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