Trowel

What Is a Trowel?

A trowel is a handheld tool with a blade and a handle designed to move, spread, shape, and smooth pastes and mixes such as mortar, thinset, plaster, and concrete. Think of it as the painter’s brush for masonry and tile work. Different trowel shapes and sizes are tuned to specific jobs: some carry and place material, others create ridges for tile, and others finish surfaces to a smooth sheen.

Common Uses in DIY and Home Improvement

• Masonry: Spreading and leveling mortar for brick and block, buttering brick edges, repointing joints.
• Tiling: Applying and combing thinset or mastic, adjusting coverage, cleaning edges.
• Plastering and skim coating: Laying on plaster or joint compound and smoothing it to a flat surface.
• Concrete: Troweling slabs, steps, and pads to tighten and smooth the surface after floating.
• Small repairs: Filling cracks and holes in masonry, patching around fixtures, and touch-ups in tight spaces.

Types of Trowels

• Brick trowel: A triangular blade used to scoop and spread mortar onto bricks or blocks; the pointed tip helps place mortar accurately.
• Pointing trowel: A small, narrow blade for detail work like repointing joints, repairs, and tight corners.
• Margin trowel: A rectangular, narrow blade with square ends; great for scraping buckets, mixing small batches, cleaning edges, and working in corners.
• Notched trowel: A flat blade with square, V, or U notches that comb thinset for tile. Notch size controls the thickness and coverage of adhesive.
• Finishing (plaster) trowel: A wide, smooth blade (often stainless steel) for applying and smoothing plaster or finishing coats.
• Pool trowel: Similar to a finishing trowel but with rounded corners to reduce gouges; often used on concrete and plaster finishes.
• Gauging trowel: A small, rounded-end trowel used to mix and apply precise amounts of plaster or mortar for patching.
• Garden trowel: A scoop-shaped digging tool for soil. It shares the name but is used outdoors for planting, not for masonry or tile.

How to Choose the Right Trowel

• Task fit: Match the trowel to the job. Bricklaying favors a brick trowel, tile work calls for a notched trowel, plaster needs a finishing trowel, and detailed repairs go smoother with a pointing or margin trowel.
• Blade material:
  • Stainless steel resists rust and is easy to clean; good for plaster and frequent washing.
  • Carbon steel is stiffer and can hold a keen edge, favored for some masonry and concrete finishing, but it can rust if not dried and oiled.
• Blade size and stiffness: Larger blades move more material but can be tiring; smaller blades offer control. Flexible blades help with finishing coats, while stiffer blades excel at placing mortar.
• Handle comfort: Try different grips (wood, rubber, or composite). A comfortable, well-balanced handle reduces fatigue during long sessions.
• Notch selection for tile:
  • Mosaics and small tile: V-notch around 3/16 in or square notch 1/4 x 1/4 in.
  • Typical wall tile or small floor tile: 1/4 x 1/4 in square notch.
  • Larger floor tile (12 x 12 in to 16 x 16 in): 1/4 x 3/8 in square notch.
  • Large format tile (long planks or 18 in and up): 1/2 x 1/2 in square notch or a slant-back ridge system; always check the mortar and tile manufacturer’s guidance.

How to Use a Trowel: Key Tips

• Troweling angle: For tile, hold the notched trowel around 45 degrees to the surface to form consistent ridges. Adjust the angle to increase or reduce adhesive thickness.
• Comb in one direction: Straight, parallel ridges help air escape when the tile is pressed in, improving coverage.
• Back-butter large tiles: For tiles bigger than about 12 in on any side, spread a thin coat of mortar on the tile back to improve bond.
• Timing in concrete: Wait until bleed water evaporates before steel troweling. Start too early and you trap water, which can lead to surface defects.
• Feathering plaster: Use a flexible finishing trowel to spread thin coats. Apply firm pressure to flatten high spots and lighter pressure to avoid ridges.
• Use the right helper tools: A hawk or mud pan keeps material handy for plaster; a margin trowel is perfect for scraping buckets and tight cleanups.

Maintenance and Care

• Clean promptly: Rinse and wipe off mortar, thinset, or plaster before it hardens. A stiff brush and a margin trowel make cleanup easier.
• Dry thoroughly: Prevent rust by drying metal blades after washing. A light coat of tool oil on carbon steel helps.
• Protect edges: Avoid prying or scraping concrete with the blade edge. Store flat or hang to prevent bending; blade guards keep edges true.
• Sharpen and dress: If the blade develops burrs or nicks, smooth them with fine sandpaper or a file. A smooth edge gives a better finish.

Common Mistakes to Avoid

• Wrong notch size for tile: Too small and you get poor coverage; too large and adhesive oozes into joints. Do a quick test by setting a tile and pulling it up—aim for near-full coverage.
• Laying thinset at the wrong angle: A nearly flat trowel leaves low ridges and weak bonds; too steep leaves excess material. Target about 45 degrees and consistent pressure.
• Over-troweling concrete: Working the surface while bleed water is present or troweling repeatedly can cause scaling or blisters. Let the surface set properly between passes.
• Using one trowel for everything: A brick trowel is not great for combing thinset, and a notched trowel is not ideal for finishing plaster. Use the style designed for the task.
• Letting material harden on the blade: Dried mortar or plaster creates bumps that scratch finishes and throw off thickness.

Related Tools and Terms

• Float: A flat tool (often magnesium, wood, or rubber) used to level or compact surfaces; in tile, a grout float presses grout into joints.
• Hawk: A flat handheld board that holds plaster close to your work area.
• Putty knife/taping knife: Flexible knives for joint compound and putty; different from trowels but sometimes used alongside them.
• Jointer: A tool that shapes mortar joints in brickwork.
• Screed: A straightedge used to level concrete or mortar beds before troweling.

Real-World Examples

• Tiling a backsplash: Use a 1/4 x 1/4 in square-notch trowel to spread thinset on the wall at a steady 45-degree angle. Comb in straight lines, set the tile with a slight slide perpendicular to the ridges, and check for coverage on the first few tiles.
• Repointing a brick step: Rake out loose mortar, then load fresh mortar onto a pointing trowel. Press it firmly into the joint, smooth with the trowel or a jointer, and brush away crumbs after initial set.
• Patching plaster: Hold a hawk under the work area, use a finishing trowel to apply patching plaster, and feather the edges thin. After it sets slightly, go back with light pressure for a smoother finish.
• Finishing a small concrete pad: After screeding and floating, wait for the sheen of water to disappear. Use a steel trowel with sweeping arcs, increasing pressure slightly with each pass to tighten the surface without bringing up water.

With the right trowel, proper technique, and quick cleanup, your masonry, tile, plaster, and concrete projects will look cleaner, bond better, and last longer.