Tiling Trowels: 5 things you should know

Tiling trowels are used to apply tile mortar to floors or walls. In addition to being used for spreading the mortar from the mixing bucket to the surface, it is also used as a “metered dispensing system”. This means it can apply the precise amount of mortar that is required. This article tries to answers a lot of the common questions about Tiling Trowels.

Trowel Uses, when do I need one?

In general, trowels are used for scooping, mixing, spreading, and skimming during tiling.

They can also be used to install many types of glass, backer board, membrane, and masonry block. A proper trowel is essential to the completion and durability of the installation.

Being a tool for tiling, trowels come in many shapes and sizes. It is important to choose a trowel that is the correct shape and size for the tile type. This article will provide you with all the essential information you might need when searching for the best trowel for your tiles.

Types Of Tiling Trowels, what type should I use?

In general, trowels come in various shapes and sizes. The three most used trowel shapes for tiling are the square notch, the V-notch, and the U-notch. A square notch trowel is mainly used for floor tiling and tiles over 2 inches square. A U-notch trowel can be used for the same tile types but delivers a little bit less mortar. A V-notch is mainly used for wall tiling and tiles under 2 inches square. It delivers less mortar than a square notch trowel. The trowel size depends on the size of the tile.

Some specialty trowels include a bucket trowel, a margin trowel, and a flat trowel. The notch shapes affect the quantity of thin-set you can spread.

Every trowel shape comes in a range of sizes. The different trowel shapes are:

● V-Notch Trowels

A V-notch trowel has V-shaped edges. This is the trowel to use when installing mosaic tile as it leaves the least amount of thin-set on the installation substrate.

The typical size of the trowel is a 3/16″ x ¼” V-notch trowel for up to 4 ½” glazed wall tile and mosaics.

● U-Notch Trowels

A U-notch trowel spreads more thin-set than a V-shaped trowel. This is why a U-shaped trowel is used for tiles larger than 4″. The biggest difference between the U-shaped and the V-shaped trowels is that the notches or teeth are different.

The following two sizes of U-shaped trowels are used commonly:

  • U- Notch Trowel ¼” x ¼” – for 4″ x4″ up to 8″ x8″ tile. This is the preferred trowel for those who want a lighter spread for floor tile OR a heavy spread for wall tile.
  • U- Notch Trowel ¼” x 3/8″ – for 8″ x8″ up to 16″ x16″ tile. This, as well, is the preferred trowel for those who want a lighter spread for floor tile OR a heavy spread for wall tile

● Square Notch Trowels

The square notch trowel has square teeth, unlike the V-notch and the U-notch. Just like the U-notch, you can use the square notch trowel for any tiles larger than 4″.

The difference between the square notch and U-notch trowel is that the square-notch spreads more thin-set than the U-notch.

The following three sizes of square-notch trowels are commonly used:

  • ¼” x ¼” Square Notch Trowel for tile 4″ x 4″ up to 8″ x 8″.
  • 1/4″ x 3/8″ Square Notch Trowel for tile 8″ x8″ up to 13″ x13″.
  • 1/2″ x 1/2″ Square Notch Trowel for 16″ x16″ and larger tile.

The following specialty trowels are also helpful.

● Specialty Trowel – Margin Trowels

The margin trowel is used to mix spread, thin-set, and scoop materials into tight spaces. There are two types of margin trowels: pointing and flat-nosed. A flat-nosed trowel is commonly used when spreading mortar in corners and tighter spaces where a larger pointed trowel might not fit. In comparison, a pointing trowel is the smaller version of the brick trowel and is used to fill in small openings and repair collapsing mortar joints.

● Specialty Trowel – Flat Trowels

A flat trowel is also called a finishing trowel and is used to smooth a surface area since it has no teeth.

● Specialty Trowel – Bucket Trowels

To remove mortar or plaster without damaging the bucket, you should use a bucket trowel. This trowel also has no teeth.

● Trowel Measurements

As already mentioned, different trowel shapes come in different sizes. The sizes, however, aren’t just a matter of small, medium, or large.

Generally, the size of a trowel depends on the size of the tiles you will work with. If you are using small tiles, you would need to pick a smaller trowel. For a large format tile, a larger trowel is needed.

Nevertheless, you have to be specific about the measurements. Trowels are measured by the height, or depth, and length of the teeth or notches. This means a  ¼” x ¼” trowel will have a notch that is ¼” square.

Tiling Trowel Size Guide

In general, you can read the size of the trowel from the name of the trowel. The first figure is the width of the notches (“the distance between the teeth”), the second figure is the depth of the notch. For example, a 1/2″ x 1/2″ square-notched trowel leaves 1/2″ ridges of thin-set on the substrate with 1/2″ spaces between each ridge.

Choosing The Right Tile Trowel Size, some helpful tips:

In general, use a trowel size that ensures at least a 85% adhesive coverage for a dry area. This is the amount of area under the tile that is covered by the adhesive. And a 95% minimum coverage for a wet area (bath surrounds, showers, etc.).

Before starting to lay tile, it is necessary to decide the type of tile trowel to use. The trickiest part is choosing the most suitable notch size for your project. Should you use a square-notched trowel or a U-notched trowel? These are common dilemmas you may face before you start your tiling project.

There is no standard trowel size for tile installation as it depends completely on the type and size of tile you are going to install. Every type of tile requires a different sized tiling trowel. The main concern is the amount of coverage for the tile.

Adequate adhesive coverage means a minimum of 85% total coverage underneath a tile for a dry area installation (fireplace, most floors, etc.) and 95% minimum total coverage in a wet area (bath surrounds, showers, etc.). In addition to these requirements, complete coverage underneath all four corners of the tile is also mandatory.

For the proper coverage, the correct size of the trowel is required. You need to find one that will give you the above-mentioned amount of coverage underneath your tiles. This is easy to check by lifting a tiles after placning it, and check the coverage underneath. There should be no more trowel lines, and you should see whole coverage of adhesive on both the substrate, and the back of the tile.

How To Measure The Size Of The Trowel?

In general, to determine and estimate the trowel’s size, you need to consider the size and spacing of the trowel’s teeth or notches. To know the trowel size, measure the width of the notches (i.e. the distance between the teeth) and the depth of the notch.

After measuring, you will know how much adhesive the trowel will leave on the substrate once you spread it out. The spacing and shape of the trowel’s tooth determine how much adhesive there is between the tile and substrate once the tile is added.

If you want 12mm ridges of adhesive on the substrate with 12mm spaces between each ridge, you should use a 12mm x 12mm square-notched trowel. A 12mmx12mm tile trowel has only one measurement (i.e., a 12mm trowel), meaning that both the measurements are the same.

A 6mm x 10mm square-notched trowel will leave you with 6mm wide by 10mm high ridges of adhesive on the substrate. And 6mm spaces between every ridge.

U-notched trowels usually only have one number, which is the measurement of both teeth. If you spread adhesive using a U-notched trowel, for instance, a 10mm trowel, you’ll see half-round ridges on the substrate. The height and space between each ridge will be the size of the trowel. The width of each ridge, however, will be DOUBLE the trowel size – 20mm.

Floor Tiling Trowel Notch Size

Use the following table to find the floor tiling trowel size:

Trowel Notch size
Tile size
6 mm notched trowel
150 x 150 mm tiles
8 mm notched trowel
200 x 200 mm tiles
10 mm notched trowel
300 x 300 mm tiles
12 mm notched trowel
400 x 400 mm tiles
15 mm notched trowel
500 x 500 mm tiles and larger

Generally, the square-notched trowels are used for most floor tiling and any tile that is over about 2 inches square. The U-notch trowel is the modification of a square-notch trowel. This distributes a bit less mortar than a square-notch and can be used in place of a square-notch.

What Notch Size Trowel For Tiling

In general, mosaic tiles up to 2 inches and wall tiles up to 4 inches can use a 1/8-inch notch. Tiles that are 16-inches need a 1/2-inch-deep notch, and any tile over 24 inches should use a 3/4-inch notch. Every tile manufacturer offers a recommended trowel size.

If you’re laying tile on a sloped floor, you would probably spread out or back-butter the mud-bed slightly thicker than the common guide that is given below:

Type of Trowel
Trowel Size
Tile Size
Type of Tile
3/16″ x 1/4″
up to 4-1/2″
3/16″ x 1/4″
Glazed wall tile
1/4″ x 1/4″
Square / U-notch
4″ to 8″
Normal Tile
1/4″ x 3/8″
Square / U-notch
8″ to 16″
Normal Tile
1/2″ x 1/2″
Square / U-notch
16″ and larger
Normal Tile

Why Use A Notched Trowel For Tiling

In general, the notches on a trowel have two significant roles. They help to apply only a specific amount of mortar, independent of the amount of mortar you put on it. And the notches on the trowel are useful to create spaces between the lines of mortar.

Some Common Questions Related To Tiling Trowels

It is normal for anyone who is not a professional but is planning to install tiles on their own to have a few questions. The most commonly asked questions are as follows:

● How to properly use a trowel, some helpful tips:

In general, pushing in the mortar using the flat side of the trowel is very important for a good chemical bond. You may add more mortar to the substrate and spread the mortar in straight lines, all going in the same direction. This will help provide better spreading of the mortar.

Do not “swirl” the mortar, as doing this will result in gaps that will prevent the tile from properly bonding to the substrate. Under normal use, this can also cause cracks in tiles.

Added “buttering” of the tile may be desired as per the wall, floor, or tile conditions.

● In what quantity do you require trowels for a tile installation project?

In general, the number of trowels required for every project varies. It mainly depends on the number of various size tiles you will be installing and how much preparation is required.

● How should one clean a trowel?

Use a hose sprayer to clean a trowel. And immediately after that, use a clean sponge with some water to finish cleaning.

Using an electric grinder becomes necessary when adhesive or mortar hardens on the trowel. With it, you can remove the hardened material from it.

● When should you replace your trowel?

It is best to replace your trowel when the edges or the square notches of the trowel are bent and/or worn.

Cleaning every tool you use is also essential. If you fail to maintain your trowels properly or use a worn trowel, you might find that the material you just applied has jerked or skid on the slab due to improper application.

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