You want to know which notched tile trowel size to use for your tile project. The boxes of tile that you buy usually don’t tell you which size trowel to use with them.
Consequently, I get asked about tile trowel sizes quite a bit.
It seems as though it’s a big secret.
Estimated reading time: 8 minutes
This post will cover:
- Why the trowels have notches in the first place
- Different sizes of notched trowels
- Common tile sizes and which notch trowels to use (subway, 12×24, etc)
Why does trowel size matter?
Different trowel sizes put down different amounts of mortar. Further, different-sized tiles require different amounts of thinset mortar to install them properly.
However, trowel size isn’t the most important factor. More important is how much mortar coverage you’re getting underneath your tiles.
What’s the proper amount of mortar to have underneath my tile?
The proper amount of mortar will embed a tile in a minimum of 3/32 inch bed of mortar. Further, the tile will be fully supported without uncontrollably oozing thinset out of the grout joints.
Watch full-length Trowel video on the DIYTileGuy Youtube Channel
What do the different trowel sizes do? This post will demonstrate the popular trowel and show how they are used.
Notched Trowel Size Guide
⅛ inch x ⅛ inch square notch trowel
This is about the smallest notch size trowel that we use in the tile world. Anything smaller is typically for glue applications.
The ⅛ inch square notch trowel is used for some thin waterproof membranes. Which ones? You’ll have to read the instructions for the brand and product that you are installing.
This trowel is also used, occasionally, for very thin glass mosaic tiles with flat backs.
Kerdi Trowel
Schluter Systems has its own branded Kerdi Trowel for installing its Kerdi Shower System. The Kerdi Trowel is simply a ⅛ x ⅛ inch square notch trowel. Remember, in addition to using unmodified mortar, Schluter now has their own brand of tile mortars, some of which are modified.
¼ inch x 5/16 inch V-notch trowel
This trowel is used for some thin waterproof membranes. Additionally, certain uncoupling membranes are installed with this size trowel. Again, you’ll need to check what the manufacturer requires for the particular membrane that you are using.
Small mosaic tiles like small, thin hex or penny round tiles are examples that would likely require this trowel size.
1/4 x 5/16th square notch trowel
This trowel size didn’t use to be common until recently. I use this trowel wherever I would use the ¼ x 3/16 inch V-notch trowel. They apply similar amounts of mortar.
Ditra Trowel
The Ditra Trowel is simply a 3/16 x 3/16 square notch trowel. Technically, they say that it’s 5/64 x 5/64. This trowel size is what you would use to install the ⅛ inch thick Ditra Membrane.
Be sure to check out my post on Ditra installation tips if this is the product that you are considering using.
See example of Ditra Trowel here.
¼ inch x ¼ inch square notch trowel
This is, quite likely, the most common size of trowel that tile setters own. We use this trowel size for:
- Cement board
- Certain uncoupling membranes
- Some of the thicker uncoupling membranes like the uncoupling heat membranes
- Some mosaic tiles typically in the 2-3 inch range
- Certain glass mosaic tiles such as the mixed linear glass mosaic tiles that you see in the video
- Subway tile and other ceramic tiles up to 6×6 inches square
- Pebble tile
- As well as other applications
See example of 1/4 x 1/4 square notch trowel here.
Ditra-Heat Trowel
The Ditra-Heat Trowel is a ¼ inch x ¼ inch square notch trowel. You would use this size with Ditra-Heat, Ditra-Heat Duo, and Ditra XL.
¼ inch x ⅜ inch square notch trowel
This trowel would be used for some of the thicker uncoupling heat membranes (check with the manufacturer).
This sized notch trowel is also great for installing 12x12s, 13×13’s, and 16×16’s.
Additionally, I like to use this size trowel for the bigger “subway” tiles such as the 4×12’s and 4×16’s.
See example of 1/4 x 3/8 square notch trowel here.
½ inch x ½ inch square notch trowel
The big ½ inch square notch trowel is used for big tiles. You want to use this for most tiles that are 16-inches and larger. So, this is a good trowel size for 12×24 tiles, 16×16’s, 6×24’s, 8×36’s, wood-look plank tiles, etc.
Additionally, it’s a good choice for natural stone tiles 12×12 and larger like marble, granite, and travertine.
Update: the 1/2 x 1/2 inch square notch trowel is no longer recommended for use. Click to see which trowels to use instead.
See example of 1/4 x 1/2 inch U-notch trowel here.
Specialty trowels
Euro Notch trowel or ‘YW’
The Euro notched trowel, sometimes called a YW trowel, is an innovation that is designed to collapse the ridges in the mortar in a more efficient way.
This type of trowel will often be specified when installing the really large thin porcelain tile panels that are becoming more popular today.
See example of Euro Notch Trowel here.
Slant notched trowel
Slant notched trowels are also designed to collapse the ridges in the mortar more easily. These trowels are a little harder to come by, though.
Margin Trowel
The margin trowel has nothing to do with combing mortar. Rather, it’s a tool that every tile setter owns and uses in a variety of ways.
It really is an essential tool for scooping mortar out of the bucket, lifting tiles, and cleaning the mortar from around the edge of the tile and, yes, mixing small amounts of mortar by hand.
Margin trowels come in two different sizes but the 5-6 inch is the most popular.
See examples of Margin Trowels here
What size trowel do I use?
Here’s a size guide for some of the different types of tile and products you may be installing.
Keep in mind, this is just for reference and you still need to check and see if the notch trowel is giving you proper mortar coverage.
What trowel size for 12×24 tile?
For the very popular 12×24 tile size you’ll want to use a 1/4 x 1/2 inch U-notch trowel, a Euro or YW notch trowel, or 1/2 x 1/2 inch notch trowel. The 1/2 x 1/2 trowel isn’t recommended though.
What trowel size for 3×6 subway tile?
This is controversial, but a 1/4 x 3/8 trowel is the best for subway tile. Yes, most recommendations will be for a 1/4 x 1/4 square notch trowel.
However, a 1/4 inch square notch lays down a very minimal amount of mortar. Combine this with the fact that most people don’t back-butter 3×6 subway tile and you have a recipe for incomplete thinset coverage on the back of your tile.
Rather, use a 1/4 x 3/8 inch square or U-notch trowel. If you find that there is too much mortar coming through the grout joints, adjust it to a 30-35 degree angle rather than 45. This angle is more natural and should make for a cleaner installation.
What size trowel for 6×24 and other plank tiles?
For porcelain plank tiles in 6×24, 9×36, 6×48, and others, you will want to use at least a 1/2 inch deep trowel like a 1/4 x 1/2 inch U-notch trowel or a Euro or YW notch trowel. The 1/2 x 1/2 trowel isn’t recommended.
You’re going to want to back butter these tiles and make sure the crown in the center is properly filled.
What trowel size for 12×12 tiles?
For most 12×12 tiles, a 1/4 x 3/8 inch square notch trowel will work great as long as the tile is flat back troweled as well.
If you are installing a heavier natural stone tile, you’ll probably want to increase the notch trowel size to 1/4 x 1/2 inch deep.
What size trowel for 2×2 mosaic tiles?
The 1/4 x 1/4 inch square notch trowel is a good choice for most 2×2 mosaic tile on sheets.
What size trowel for penny tiles and small hex tiles on sheets?
For small porcelain penny and hex tiles, I like the 1/4 x 5/16 V-notch trowel or the 3/16 x 3/16 inch square notch (Ditra) trowel.
What trowel size for 4×12 and 4×16 large subway tiles?
For the larger subway tiles, the 1/4 x 3/8 inch deep trowel size works great. You might even experiment with the 1/2 inch deep version if you find you aren’t getting proper mortar coverage.
Square notch vs U-notch trowels
There’s very little difference between a square notch trowel and a U-notch.
Some argue that the U-shape collapses better. However, a counter-argument is that the square shape leaves slightly more mortar underneath the tile.
Bottom line: I wouldn’t worry about square vs U. The square notch is more popular in most trowels. One exception is the 1/4 x 1/2 inch size where the U-shape notches seems to be more available.
