Primo Tools 11/64" Square Notch Trowel — The Membrane Notch That Won't Break the Bank

Uncoupling membrane lives or dies on notch size. Too little mortar and the anchoring fleece never keys in — you get a bond that lets go under the tile you just set. Too much and it squeezes up and floods the waffle cavities the membrane needs to do its job. The 11/64" x 11/64" square notch is the size that gets it right, and this trowel delivers it without a specialty-brand price tag.

The rigid steel blade is the part that matters day to day: it holds its notch depth across a whole floor instead of flexing and wandering, so the ridges you comb at the far wall look like the ones you combed at the door. The same fine notch also suits mosaics, small-format tile, and thin-bed work. Working with waterproofing membrane instead? The 1/8" square notch is the finer companion, and a forged margin trowel handles the corners and cut-ins this one can't reach.

Why Tile Pros Choose It

• Membrane-ready notch: 11/64" square — the size uncoupling membrane calls for
• Even coverage: Precision-cut notches keep ridge height consistent
• Rigid blade: Minimal flex means the same bed from wall to wall
• Versatile: Also suits mosaics, small-format, and thin-bed work
• Daily driver: Built for professional use, priced like a tool you'll actually replace
• Does one job properly: Which is more than most trowels in the bucket can say

Pro tip: Comb in one direction and press the membrane in with a float, then pull a corner back on your first sheet to confirm full mortar transfer across the fleece. Keep the notches scraped clean — dried thin-set quietly shrinks your coverage.