Installing a subway tile backsplash can add a classic, timeless look to your kitchen or bathroom. Subway tiles are rectangular tiles that are sized similarly to the tiles used in subway stations, typically 3×6 inches or 4×8 inches. When installing 3×6 subway tiles for a backsplash, choosing the right trowel size is important to get proper coverage of the thinset mortar and a strong bond.
Introduction
When installing subway tile, the trowel size determines how much thinset mortar is applied to the wall and back of each tile. Using the right trowel size results in good coverage and adhesion. Choosing too small of a trowel can lead to poor adhesion, while too large of a trowel causes thinset to squeeze up between tiles creating a mess to clean up.
The proper trowel size depends on several factors:
- Tile size – 3×6 subway tiles are a small format tile which requires a smaller notch trowel size.
- Tile material – Natural stone tiles require a thicker layer of thinset than ceramic or porcelain.
- Tile surface – Tiles with very uneven backs require more thinset.
- Wall surface – Painted drywall requires a thicker thinset layer than cement board.
For a 3×6 glass, ceramic, or porcelain subway tile backsplash on cement board, experts generally recommend a 1/4” x 3/8” square or U-notched trowel. However, you should also check the tile manufacturer’s recommendations to ensure proper installation and coverage.
This article provides detailed information on choosing the right trowel size for 3×6 subway tile backsplash installations. We’ll cover the importance of trowel size, how to determine the best trowel size, trowel options, how to use a notched trowel, and tips for achieving full mortar contact and proper tile spacing when installing 3×6 subway tile.
The Importance of Using the Right Size Trowel
Using the properly sized trowel is imperative to achieve proper thinset coverage and a lasting tile installation. Insufficient coverage can lead to hollow spots, cracked grout, and tiles popping off the wall. Too much thinset leads to difficulty cleaning up.
The notched edges on the trowel create ridges and valleys in the thinset allowing it to adhere properly to both the wall and the tile. The height of the notches and width between them determine the right amount of mortar coverage.
When setting 3×6 subway tiles, the small size and smooth back surfaces allow for a relatively thin layer of thinset. A trowel with 1/4″ high notches and 3/8″ spacing between them typically provides full coverage without overloading the tiles with thinset.
Choosing the right trowel ensures:
- Complete coverage of the tile backs so no hollow spots develop.
- Adequate bed thickness for the tile size and surface variation.
- Consistent thickness across the installation for even adhesion.
- Efficient use of thinset mortar without waste.
- Minimal need to back-butter tiles.
- Smooth installation without lippage between tiles.
- Neater final results with minimal squeeze out.
Investing in a quality notched trowel specifically sized for your tile project results in easier installation and better long-term performance.
How to Determine the Best Trowel Size
Choosing the proper trowel size involves considering the recommendations from the:
- Tile manufacturer – The tile packaging or documentation often indicates the recommended trowel size.
- Thinset manufacturer – The thinset packaging and documentation specifies trowel size recommendations.
- TCNA handbook – The Tile Council of North America Handbook has guidelines on trowel sizes for different tile applications.
You also need to factor in the tile material, thickness, surface texture, the substrate, and environmental conditions.
Here are some general tips on determining the best trowel size for 3×6 subway tiles:
- For ceramic, porcelain, or glass 3×6 subway tiles, a 1/4″ x 3/8″ square or U-notched trowel is typically recommended.
- Larger tiles and natural stone tiles require larger notches, up to 1/2″ square or U-notches.
- Small mosaic tiles use smaller 1/8″ V-notches.
- Heavily textured tile backs need thicker thinset layers, potentially up to 3/8″ U-notches.
- Walls with imperfections like painted drywall require more thinset to fill the voids, around 3/8” notches.
- Cement backer board provides an even surface that needs less thinset, allowing 1/4″ notches.
- In hot, dry climates, slightly larger notches help account for faster thinset drying.
- Cold, humid climates can use smaller notches as thinset stays workable longer.
Always verify the recommendations from manufacturers and install guides to select the optimal trowel size. Also check requirements for the grout joints as wider grout lines need deeper notches.
Trowel Options for 3×6 Subway Tiles
There are a few types of trowels used for applying thinset when installing 3×6 subway tile backsplashes:
Square Notch Trowel
A square notch trowel has flat squared off teeth cut into the blade. The square shape helps maintain consistent depth across the trowel’s width. The most common square notch size used for 3×6 subway tiles is 1/4″ x 3/8″.
U-Notch Trowel
A U-notch trowel has semi-circular notches cut into the blade. The rounded notches make it easier to produce even ridges in the thinset. A 1/4″ U-notch trowel is ideal for 3×6 subway installations.
Euro Notch Trowel
Euro notch trowels have elongated U-shaped notches turned upward on theblade. The euro notch shape can help minimize thinset squeeze-up between tiles. Common euro notch sizes are 4-5mm for small mosaics and 6mm for standard tiles.
Look for trowels with comfortable rubber handles for ease of use. Rigid one-piece steel blades resist flexing during use for consistent thinset layers. Stainless steel resists corrosion from the cementitious materials.
Purchase trowels from reputable manufacturers like Marshalltown, Raimondi, Margin, and Bon Tool. Also consider trowel saver tools for smoothing notches and cleaning after use.
How to Use a Notched Trowel
Using a notched trowel properly is just as important as selecting the right size. Here are some tips for achieving full thinset coverage when installing 3×6 subway tile:
- Apply a thin skim coat of thinset to the wall first using the flat side of the trowel. This helps prime the surface.
- Hold the trowel at a 45° angle and firmly press into the thinset to form the notched ridges.
- Apply only as much thinset as can be covered with tiles before drying, usually a few square feet.
- Use the trowel ridges as a guide to check for 100% thinset contact on tile backs before placing on the wall.
- After setting tiles, use the flat side of the trowel to scrape excess thinset from grout joints.
- Use a notched trowel edge tool to smooth ridges and clean the blade.
- Discard excess thinset as hardened material prevents proper notching.
Taking the time to learn how to handle a notched trowel makes achieving the proper thinset consistency much easier for first-time installers.
Achieving Full Mortar Contact
In addition to using the correctly sized trowel, here are some tips to help ensure proper thinset coverage on the backs of 3×6 subway tiles:
- Inspect tile backs – Check for unevenness or texture that requires extra thinset.
- Back-butter tiles – Spread additional thinset on heavily textured or warped tiles before placing them on the wall.
- Use tile spacers – Plastic tile spacers help maintain even grout joint widths necessary for thinset coverage.
- Check thinset ridges – Verify tiles have fully embedded into the thinset ridges before adjusting placement.
- Avoid “walking” tiles – Don’t slide tiles back and forth after placing them as it disrupts mortar contact.
- Use a grout float – Fill any gaps in thinset with a grout float to prevent voids under tiles.
- Inspect from corners – Visually check thinset contact from tile corners before grouting.
Taking extra care during the installation process ensures every tile achieves maximum thinset coverage and adhesion to the wall.
Proper Tile Spacing with Correct Trowel Size
The height of the trowel notches establishes the appropriate grout joint width between 3×6 subway tiles. Consistent grout lines result in a clean, professional look.
Here are some tips for maintaining proper tile spacing when using a notched trowel:
- Select a trowel size to achieve the desired grout line width. Typical sizes are 1/16” or 1/8”.
- Use plastic tile spacers inserted between tiles to maintain even grout joints.
- Arrange tiles on the wall within the open time of the thinset before it skins over.
- Avoid adjusting or moving tiles after placing them which can shift spacing.
- Use a tile leveling system to keep tile surfaces flush.
- Clean excess thinset from grout joints with a trowel edge as you work to prevent thinning the joints.
- Before grouting, inspect the grout lines for proper width and consistency.
The correct trowel size, careful tile placement, and attentive joint spacing results in straight, uniform grout lines between 3×6 subway tiles.
FAQs
What size notched trowel do I use for 3×6 subway tile?
For 3×6 ceramic, porcelain, or glass subway tile, a trowel with 1/4″ square or U-shaped notches spaced 3/8″ apart is recommended. Always check manufacturer guidelines.
Can I use a 1/4″ V-notch trowel for 3×6 subway tile?
A V-notch trowel is not ideal. The thinset left by a V-notch does not provide as much coverage across the small tile surface as the ridges from a square or U-notch trowel.
What if my tiles have lipped or uneven edges?
Tiles with significant texture, lips, or unevenness may require back-buttering each tile with additional thinset before placing them on the wall. Use a wider grout joint as well.
How do I get full thinset coverage on glossy tile backs?
Glossy or polished tile backs can be more difficult to bond thinset to. Take extra care back-buttering each tile and firmly pressing tiles into the ridges to get full mortar transfer.
Can I use a thinner thinset layer on cement board?
Yes, cement board provides a very evenly surfaced foundation that requires less thinset depth than drywall. A slightly smaller notch trowel may be acceptable on cement board.
What do I do if tiles shift after placing them on the thinset?
Avoid sliding tiles after initial placement as it disrupts the mortar ridges. If a tile does shift, carefully lift and re-apply it into the thinset ridges, then use spacers to hold it in place.
Conclusion
Choosing the proper trowel size is a key factor for successful 3×6 subway tile backsplash installations. Using the right trowel allows you to achieve full thinset coverage on the backs of the small tiles for a strong bond. A 1/4″ x 3/8″ square or U-notch trowel is the ideal size for most standard 3×6 subway tile applications. With the right trowel, you can create a stunning backsplash that lasts for years to come.