Why does trowel size matter? The notches are important on trowels. They leave an even and consistent amount of mortar down to set your tiles into. ... Furthermore, the purpose of the notches is to give the mortar a place to “collapse into” once the tile is installed and compressed down.

Why do you need to use a notched trowel?

A notched trowel is used to spread adhesive and thin set. It differs from a regular trowel in that it has notches, usually on two sides of the blade. Running a notched trowel over adhesive or thinset leaves behind rows of the product.

Why do you put grooves in tile mortar?

Why? Because trowel ridges running in straight lines are much easier to collapse. They also assist with air removal so you can maximize mortar coverage and ensure a strong bond to the tile and substrate.