Choosing the right trowel size is an important decision when installing 3×12 subway tile for your backsplash. The trowel determines how much mortar will be applied to the wall, which allows the tiles to adhere properly. Using the correct trowel size leads to a quality installation that lasts for years to come. In this article, we’ll cover everything you need to know about selecting the ideal trowel for your 3×12 subway tile backsplash project.
Introduction
A subway tile backsplash can add a classic, timeless look to any kitchen. The rectangular 3×12 size provides a versatile shape that fits well in both traditional and modern spaces. While the tile itself is an important choice, having the right trowel to apply the mortar during installation is just as critical.
Using a trowel with the proper thickness will help ensure full coverage of the mortar on the wall and proper adhesion for the tile. The right amount of mortar is key – too little and the tiles won’t stick well, too much and you’ll have a mess of squeezed out mortar.
Choosing the correct trowel size depends on the type of subway tile, the size, thickness, and layout pattern. In general, a 1/4″ or 3/8” square-notched trowel is recommended for most standard 3×12 subway tile backsplash installations. We’ll go over the specifics in more detail throughout this article.
What is a Tile Trowel?
A tile trowel is a hand tool used to spread and apply mortar or adhesive onto surfaces in preparation for setting tiles. It consists of a flat, rectangular steel blade with notches along one edge that determine the thickness of the applied mortar.
The notches create grooves that mortar can sit in before the tile is placed. As you use the trowel to spread the mortar, these notches essentially comb the material onto the surface in straight rows.
Tile trowels come in a range of notch shapes (square, U-shaped) and sizes (1/16”, 1/8”, 1/4″, 3/8” etc.) to allow for variations in tile types and applications. The proper trowel helps distribute just the right amount of adhesive for the specific tile.
Benefits of Using the Right Size Trowel
There are a few key reasons why using the correctly sized trowel for your subway tile project is so important:
Achieves Proper Coverage
The thickness of the trowel determines how much mortar is applied to the wall surface. The right depth provides full coverage across the entire area so all tiles will adhere.
Too little mortar from an undersized trowel can lead to gaps, which causes tiles to loosen or fall off over time.
Avoids Excess Mortar
A trowel that deposits too much mortar will create a mess when setting the tiles. The excess will get squeezed out between the tile and wall and need to be constantly cleaned up.
Provides Even Application
The notches on the trowel blade help apply the mortar evenly across the wall surface. Consistent depth and coverage allows for a professional looking finish.
Creates Proper Bond
The appropriate thickness of mortar allows the tile to fully bond and cure properly on the wall. A quality bond ensures tiles don’t crack or detach.
Leads to Long-Lasting Finish
Choosing the right trowel promotes better adhesion and curing of the mortar for a finish that will last for many years without issues.
What Size Notch Trowel for 3×12 Subway Tile?
For a standard 3×12 glossy subway tile installed in a basic brick pattern on a wall, a 1/4″ or 3/8” square-notched trowel is recommended. Here’s an overview:
- 1/4″ square notch – Best for 3×12 subway tiles that have a thickness of 1/4″ or less.
- 3/8” square notch – Provides a thicker layer of mortar that is ideal for 3×12 tiles with slight irregularities on the back or tiles that are mounted offset from each other.
The square notches on these sized trowels allow you to apply an even 3/32” or 1/8” thick layer of mortar to the wall surface. This is the ideal depth for good coverage without creating excess.
For specialty tiles or unique applications, the trowel size may vary. We’ll go over some of those situations later in the article. But for standard smooth-backed 3×12 subway tiles, a 1/4″ or 3/8” square notch is recommended.
Factors That Determine Trowel Size
While the 1/4″ or 3/8” square notch trowels work for most cases, there are some factors that may require using a different size trowel for your 3×12 subway tile backsplash:
Type of Tile
- Stone or textured tiles – Often require a thicker layer of mortar to account for the irregular thickness. May need a 1/2″ square notch trowel.
- Mosaic tiles – Require a thinner spread of mortar to avoid oozing between small grout lines. A 3/16” or 1/8” notch is best.
- Porcelain or glass – Often have very smooth, flat backs so require less mortar. A 1/4″ notch is usually sufficient.
Tile Size
Larger tiles need a thicker layer of mortar for support.
- Smaller mosaic tiles – 3/16” to 1/4″ notch
- Standard 3×12 subway – 1/4″ or 3/8” notch
- Larger tiles 6”x6” or more – 1/2″ notch
Tile Layout Pattern
- Basic grid or brick patterns allow use of a smaller notch trowel like 1/4″ or 3/8”.
- More complex or offset layouts may require a slightly thicker mortar layer with a 1/2″ notch.
Type of Mortar
Premixed lightweight mortars or mastics can be applied thinly. Traditional mortar mixes need to be applied thicker.
Tile Thickness
Thicker tile sizes over 1/4″ thick may require a larger notch like 3/8” or 1/2″ to account for the added depth.
Surface Type
- Drywall requires a skim coat layer so only a thin layer of mortar needed.
- Concrete, plaster walls need more mortar to account for unevenness.
Consider all these factors to determine the ideal trowel size for your specific backsplash tile project.
How to Choose the Right Trowel Size
Follow this simple process to select the proper trowel for your 3×12 subway backsplash:
1. Gather Tile Specs
Have the tile size, thickness, and type handy to reference. For 3×12 subway tile, it is typically 1/4″ thick or less. Make sure to account for tile irregularities.
2. Determine Layout
Will you use a basic brick pattern or unique offset layout? Simple grids allow thinner mortar than offset patterns.
3. Check Surface
Is the wall surface smooth drywall or an uneven plaster wall? This impacts mortar needs.
4. Choose Trowel Type
For 3×12 subway tile, a square-notched trowel is recommended as a starting point.
5. Select Notch Size
Using the tile specs, layout, and surface, choose your notch size, usually 1/4″ or 3/8” for 3×12 subway.
6. Adjust as Needed
Make adjustments if needed once tiling begins. Increase notch size if coverage is uneven.
Following these simple steps will help you select the right trowel for a quality 3×12 subway tile backsplash installation. Don’t be afraid to change trowels if the initial results are unsatisfactory.
Trowel Size Recommendations for Common Installations
Here are some general trowel size recommendations for the most popular backsplash installations:
- 3×6 subway tile – 3/16” or 1/4” square notch
- 4×12 subway tile – 1/4” or 3/8” square notch
- Standard 3×12 subway – 1/4″ or 3/8” square notch
- Mosaic tiles – 3/16” square notch
- Penny tiles – Thin 3/16” notch
- Carrara marble – 3/8” square notch
- Travertine – 1/2″ square notch
- Peel-and-stick – 1/16” square notch or less
These are general guidelines only, the exact trowel size should be chosen based on your specific tile properties and project needs. When in doubt, begin with a smaller size for thinset applications.
Key Considerations When Choosing a Tile Trowel
- Always follow the tile manufacturer’s recommendation for mortar thickness if one is provided. Their guidance takes precedence.
- Allow for some tile irregularity in thickness. A slightly bigger trowel notch leaves wiggle room.
- Consider the sub-surface material and condition to determine mortar needs.
- Start with a smaller trowel size for thinset mortar installations and adjust as needed.
- The trowel notch shape (square vs U) impacts spread pattern but not thickness.
- Take time to “back butter” tiles with mortar for challenging surfaces.
Choosing the right trowel takes consideration but will lead to a quality backsplash installation. Don’t hesitate to adjust your trowel as needed once laying tile.
Trowel Size Differences
It’s helpful to visualize the various trowel sizes against each other to understand the mortar thickness differences:
As you go up in trowel size, the thickness of the resulting mortar layer increases:
- 1/16” trowel – Skinny layer for mosaics
- 1/8” trowel – Light coverage for smooth tiles
- 3/16” trowel – Medium thickness for regular mosaics
- 1/4″ trowel – Standard size for subway tiles
- 3/8” trowel – Somewhat thicker layer for offset tiles
- 1/2″ trowel – Thickest coverage for natural stone
Use this comparison to select the proper notch size for your project. Consider sizing up for tricky surfaces or thicker tiles.
Trowel Notch Shapes
In addition to notch size, trowels also come in different notch shapes that impact mortar spread:
Square Notch
Square notches are the most common. They allow you to spread mortar evenly in straight rows. Ideal for beginners.
U-Notch
The U shape causes mortar to spread in a fanning pattern. Good for covering uneven surfaces.
Half-Moon Notch
Half-moon notches spread mortar in curved rows. Useful for creating even coverage.
The shape is mostly personal preference and does not impact thickness. Pick a shape that allows you to spread mortar most effectively.
How Deep Should Mortar Be for Subway Tiles?
As we’ve discussed, for a typical 3×12 subway tile installation, the mortar should be between 3/32″ to 1/8″ thick after being combed on the wall. This depth provides full, even coverage without creating excess mess.
Here is a quick reference:
- 3/16” notch trowel = 3/32” mortar depth
- 1/4″ notch trowel = 1/16” mortar depth
- 3/8” notch trowel = 3/16” mortar depth
- 1/2″ notch trowel = 1/4″ mortar depth
Keep this mortar thickness in mind as you choose your trowel size. The notch indicates the finished depth for smooth application of subway tiles.
How to Use a Tile Trowel
Once you’ve selected the right size trowel for your backsplash project, make sure you know how to properly use it to spread the mortar:
Step 1: Apply a Workable Amount
- Spread a workable amount of mortar along the length of the wall, 2-3 square feet.
Step 2: Hold Trowel at 45 Degree Angle
- Hold the trowel at a 45 degree angle to the wall surface.
Step 3: Apply Even Pressure
- Apply even pressure while gliding the trowel across the area to evenly comb the mortar.
Step 4: Maintain Consistency
- Use the same pressure and speed throughout troweling to ensure consistent mortar thickness.
Step 5: Check Application
- Visually inspect that proper coverage is achieved with no gaps or thick spots.
Step 6: Repeat Across Surface
- Clean trowel and repeat process in sections across the entire backsplash surface.
With practice using the trowel at a consistent angle and pressure, you can achieve a smooth professional application of mortar ready for subway tile.
Frequently Asked Questions
Should I use mastic or thinset for my subway tile backsplash?
Thinset mortar is preferred, as it provides a much stronger bond than mastic. Mastic is brittle when cured and more likely to fail over time. Thinset offers superior strength and adhesion.
How long does mortar need to dry before applying tile?
Tiles can be applied to the mortar right away, no drying time is required for thinset. Just be sure to occasionally lift a tile to check its adhesion.
What’s the best mortar for subway tile backsplash?
Choose a polymer-modified mortar, which offers flexibility and higher bond strength. Modified thinset is ideal for most subway tile backsplash installations.
Do I need to seal my subway tile backsplash?
Sealing is not necessary for glazed ceramic or porcelain subway tiles. Unglazed tiles can benefit from sealing to prevent staining. Use a compatible grout sealer on sanded grout joints.
How do I cut subway tiles?
Use a wet tile saw fitted with a porcelain blade to accurately cut subway tiles. Mark the tile where cutting is needed and follow wet saw guidelines for smooth cuts.
Conclusion
Determining the right trowel size is a key step in achieving a successful 3×12 subway tile backsplash installation. With the proper thickness of mortar combed onto the wall, your tiles will adhere cleanly and neatly.
For most standard 3×12 subway tile projects, a 1/4″ or 3/8” square-notched trowel is recommended. This provides the ideal mortar depth for setting without creating excess. Consider tile properties and layout when selecting a trowel size.
Applying mortar uniformly across the surface using the appropriately sized trowel at a 45 degree angle is important for proper coverage. Take care that the mortar thickness remains consistent.
Choosing and using the right tile trowel allows you to create a stunning, long-lasting subway tile backsplash. With a quality mortar application, your tiles will maintain their bond for years to come.