Understanding this concept is key to understanding the type of notched tile trowel to use. Tile trowels come in two basic types—square-notch and V-notch—along with various sizes for each type of notch.
How a Tile Trowel Works
A tile trowel is similar to other types of masonry trowels in that it has a handle and a flat metal plate and is designed for scooping up and spreading mortar onto a relatively smooth surface. Though a notched tile trowel does have scooping abilities, it cannot be compared to other implements, such as margin trowels, that also scoop and spread. A V-notched or square-notched tile trowel has one unique feature: notches. The notches do two important things. First, they make it easy to apply only a specific amount of mortar. No matter how much mortar you pile onto the surface, the notches apply the mortar in perfect, even lines of identical thickness. When the edge of the trowel is held firmly against and dragged along the substrate, only a precise amount of thinset ends up on the surface. Excess thinset either piles up in front of the trowel or gets pushed to the sides. Second, the trowel creates spaces between the lines of mortar. These allow air to escape when the tile is pressed into the mortar. Without the spaces, you could get air pockets that prevent the tile from lying flat or adhering properly.
Square-Notch Tile Trowels
Square-notch trowels have square or rectangular notches that create mortar rows with flat spaces between them. They typically dispense more mortar than V-notch trowels, and the spaces between rows leave more room for the mortar to smush down. As a general rule, square-notch trowels are used for most floor tile and any tile over about 2 inches square. A variation of a square-notch trowel is the U-notch trowel. This delivers a bit less mortar than a square-notch and can be used wherever a square-notch makes sense.
V-Notch Tile Trowels
V-notch trowels have a continuous zig-zag or sawtooth pattern with points. They are typically used for small tiles, such as mosaics, or any tiles under 2 inches square. Because V-notch trowels dispense less mortar than square-notch, they are also preferred for many wall or ceiling applications. V-notch trowels are also easier to handle than square-notch trowels because they are moving and extruding less thinset mortar. V-notch trowels with soft, plastic handles are recommended to make them easier to hold.
How to Read Notch Sizing
Square-notch trowels often have three numbers indicating the size and spacing of the notches. The first number is the width of each tooth; the second is the spacing between teeth; the third is the depth of the teeth. If only two numbers are given, the first indicates the width of the teeth and the spacing (which will be the same), and the second is the tooth depth. V-notch trowels typically have two numbers. The first number is the width of the notches. The second number is the depth of the notches.
How to Choose a Tile Trowel Notch Size
Choose a notch size based on the tile and the installation location. Your tile supplier can recommend an appropriate size for your project. The best way to confirm that you have the correct notch size is to install a few tiles, then lift them and see how much mortar contacts the tile and the underlying surface—known as the coverage. Tile in dry locations should have at least 80-percent coverage. In wet locations, tiles need at least 95-percent coverage. This means that no more than 20-percent or 5-percent, respectively, of the tile, should be dry (without mortar). Regardless of the coverage amount, all corners of each tile must have coverage.
How to Use a Square- or V-Notch Tile Trowel
Tips For Using Notched Trowels
Hold the trowel at an angle to the substrate, never flat.Pull the trowel toward you or to the side. Do not push it away from you.Keep trowel washed off, clean, and dry between uses to prevent rusting.If the trowel is hard to move, you may be using too much thinset mortar. Or the mortar may have been mixed up too dry. If the thinset is dry and it is a new batch, add a little water to thin it down.Use latex, nitrile, or other waterproof gloves for better grip.
