How do notch and square-edged trowels differ in application?

• A. They are the same in function.
• B. Notch trowels are used for finishing; square-edged trowels create ridges.
• C. Notch trowels create adhesive ridges for proper tile adhesion; flat or square-edged trowels give back-buttering surfaces or finish to even out substrate.
• D. Only notch trowels are ever used in tile work.

Answer: (C)

Notch versus square-edged trowels relate to how adhesive is applied and bonded to the tile. A notch trowel leaves ridges of mortar on the substrate; when you press the tile down, those ridges collapse and you end up with a uniform layer of adhesive behind the tile. This method helps control the adhesive thickness and ensures good coverage across the back of the tile, which is essential for a solid bond, especially with varied tile sizes and substrate conditions.

A flat or square-edged trowel spreads adhesive as a smooth, even coat. It’s used for back-buttering or finishing to even out the substrate or the tile back, helping achieve full contact on irregular surfaces or for large-format tiles where you want to improve bond quality by ensuring a continuous adhesive film.

So, notch trowels create adhesive ridges for proper adhesion, while flat/square-edged trowels provide a smooth, even surface for back-buttering or finishing.