Pick the wrong trowel and you either starve the tile of mortar or burn through bags of thinset for nothing. The notch is what controls how much material stays on the floor, so it is worth choosing on purpose. Here is how installers think about it.
Start with the label, not the trowel
The thinset or adhesive manufacturer usually tells you which notch to use, and the tile manufacturer may have its own recommendation. When the two disagree, follow the one that carries the warranty for your job. Read the bag before you grab a trowel off the truck, because the label is the first answer to this question.
Match the notch to the tile
As a general rule, bigger tile needs a bigger notch. Small mosaics and thin wall tile sit on a shallow notch. Medium floor tile steps up to a mid-size notch. Large-format tile needs a deep notch so the mortar can collapse and fill the space under the tile. The tile back matters too. Tile with a deeply ribbed or uneven back often wants more mortar than a flat, smooth back.
Notch size alone is only a starting point. Your job conditions change the answer, so treat any chart as a place to begin and not a final call.
Square, U and V notches
Square notch trowels leave tall, straight ridges. They are the common choice for floor tile and bigger formats because they hold a lot of material. U notch trowels leave rounded ridges and are often used for adhesives where the label calls for them. V notch trowels leave a thinner, pointed ridge and tend to be used for smaller tile and thinner beds.
The Russo Comfort Grip Tile Trowel is offered in several notch styles, including square, U and V options. You can see the exact sizes on the listing for the Russo Comfort Grip Tile Trowel.
Check coverage, then adjust
The only way to know your notch is right is to check coverage. Set a tile, press it in, then lift it and look at the back. You want the mortar to have spread across the tile back, with no big bare patches. If you see ridges that never flattened, the mortar is too thin, the open time ran out, or the trowel is too small for that tile. Then size up the notch or change your technique.
Do this check at the start of every job and again whenever you change tile, thinset or substrate. It takes a minute and saves a lot of callbacks.
Technique matters as much as notch
Comb the mortar in one direction with the trowel held at a steady angle. The angle controls ridge height, so holding it consistently gives you consistent ridges. Set the tile and move it across the ridges, not along them, so air has a way to escape. For larger tile, many installers also flat-skim a thin layer onto the substrate first and back-butter the tile. Back-buttering means putting a thin coat of mortar on the back of the tile before it goes down. Whether you need it depends on the tile and the manufacturer's instructions.
Medium and large format options
Two Bihui trowels in our tile tool lineup cover the middle range. The Bihui PTSB03 1/8 inch square notch trowel leaves even ridges and suits medium adhesive applications, according to its listing. For bigger tiles that need more adhesive, the Bihui PTSB45 11/64 inch square notch trowel lays down a thicker bed. Both have an 11 inch by 4.75 inch blade.
Keep trowels clean and check for wear
Notches wear down with use, and a worn trowel quietly leaves less mortar than you think. Clean the trowel often so dried thinset does not change the ridge shape. If you notice the teeth rounding off, replace the trowel. Many installers carry a spare in a couple of common sizes so they never have to work with a worn one.
Do not forget a flat substrate
A trowel cannot fix a bad floor. If the substrate is out of flat, the notch only hides it for a while. Get the surface flat first, and use a leveling system to keep neighboring tiles in the same plane. We carry tile leveling systems and spacers for that.
Quick checklist
- Read the thinset and tile labels first.
- Start with a notch sized to the tile, and go bigger for larger or uneven-backed tile.
- Lift a tile and check coverage before you commit to a full area.
- Comb in one direction at a steady angle.
- Replace worn trowels.
Browse the full range of tile and stone tools, or contact us if you want help picking a trowel for your next job.