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How to Tile a Bathroom Floor

Home/Resources/Bathroom/Tiling a Bathroom Floor
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Written & researched by Priya Anand DIY & Tools Editor
Updated August 2026
Wide environmental view of a person's hands fitting a new shower head in a tiled bathroom, in soft overcast light

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Tiling a bathroom floor is an intermediate DIY project spanning a weekend once you include substrate prep and cure times, with materials commonly running $3 to $15 per square foot. The layout and tile-setting are learnable, but the make-or-break work is what goes underneath: a rigid, waterproofed substrate. A standard bathroom floor is DIY-friendly; a curbless wet room or a shower floor with a drain involves waterproofing that is governed by code and is best left to a tile pro. Get the prep right and the tile lasts decades; skip it and it cracks in a season.

How to Tile and Grout a Bathroom Floor — Complete Beginners Guide

Step-by-step: setting a bathroom floor

  1. Prep and stiffen the subfloor. Remove the old flooring, screw down any loose plywood, and confirm the floor does not bounce. Over plywood, install cement backer board in a bed of thinset and screw it every 8 inches, or roll out an uncoupling membrane per its instructions.
  2. Waterproof. For a bathroom floor, apply a liquid or sheet waterproofing membrane over the substrate, lapping it up the walls a couple of inches and around the toilet flange. This is required in wet zones and wise everywhere in a bathroom.
  3. Dry-lay and plan the layout. Find the room's center lines, dry-lay tiles with spacers, and adjust so you avoid thin slivers at the visible walls and center the pattern on the main sightline. Mark reference lines.
  4. Mix thinset. Mix modified thinset to a creamy, ridge-holding consistency, let it slake per the bag, and remix. Only mix what you can set before it skins over.
  5. Comb and set tile. Spread thinset with the correct notched trowel (1/4-inch notch for small tile up to 1/2-inch for big format), combing in one direction. Press each tile with a slight twist, using spacers, and check for full coverage by lifting one occasionally.
  6. Keep it flat. Lay a level or straightedge across tiles as you go and tap high tiles down with a rubber mallet and beating block. Leveling clips help with large-format tile.
  7. Cut around obstacles. Measure and cut border and toilet-flange tiles with a wet saw or snap cutter, leaving the flange opening clean.
  8. Cure, then grout. Let thinset cure 24 hours, remove spacers, and grout with sanded or unsanded grout matched to your joint width, floating it in diagonally and sponging clean.
  9. Caulk, cure and seal. Fill the wall-to-floor perimeter with silicone rather than grout, let grout cure 48 to 72 hours, then seal cement grout before returning the toilet and fixtures.
Overhead view of a person's hands fitting a new shower head in a tiled bathroom, in soft overcast light

Tools and materials

You need a notched trowel sized to your tile, a wet saw or snap cutter, a rubber mallet and beating block, tile spacers or leveling clips, a level, a grout float and sponges, cement backer board or an uncoupling membrane, thinset, a waterproofing membrane, grout, and silicone for the perimeter. Tiling the floor is usually one piece of a bathroom refresh, so it often runs alongside the fixture work in this hub; a fresh floor pairs with the ventilation and shower upgrades owners tackle at the same time, such as those in our exhaust fan roundup and shower head roundup.

Wide environmental view of a person's hands fitting a new shower head in a tiled bathroom, in warm late-afternoon light

Substrate, waterproofing and code

Everything below the tile is what determines whether it lasts. Set tile only over a rigid substrate, cement backer board or an uncoupling membrane, never bare plywood or vinyl, and confirm the floor structure is stiff enough (the tile industry uses an L/360 deflection limit). Add a waterproofing membrane on a bathroom floor. Inside a shower or a curbless wet room the waterproofing must be a continuous, code-compliant system tied into the walls and drain, and those requirements are jurisdiction-specific, so check local code. Shower-pan and wet-room waterproofing is a job many homeowners hand to a tile professional, and a failed pan is an expensive, hidden repair.

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More from this hub: Bathroom · Regrouting tile · Replacing a cracked tile · Installing a shower niche · Best exhaust fans · How we rank

Straight Answers

Frequently Asked

What goes under bathroom floor tile?

Tile needs a rigid, stable base. Over a plywood subfloor you install either a cement backer board (such as 1/4-inch or 1/2-inch cementitious board) set in thinset and screwed down, or an uncoupling membrane like a dimpled orange sheet, before you tile. You do not tile straight onto plywood or vinyl, because those flex and the grout and tile crack. The floor structure below should also be stiff enough that it does not deflect; the tile industry uses an L/360 deflection limit. For a full wet bathroom, add a waterproofing membrane over the substrate as well.

Do you need to waterproof a bathroom floor before tiling?

For a standard bathroom floor outside the shower, a proper cement-board or uncoupling-membrane substrate is the minimum, and adding a liquid or sheet waterproofing membrane is strongly recommended because bathroom floors get splashed and mopped. Inside a shower or a curbless wet room, waterproofing is mandatory and governed by tile-industry standards and local code, with the membrane tied into the walls and drain. Grout and tile are not waterproof on their own; water passes through grout, so the membrane below is what actually protects the subfloor from rot.

What size notched trowel should I use for floor tile?

Match the notch to the tile size. As a rough guide, a 1/4-inch by 1/4-inch square-notch trowel suits small tiles up to about 8 inches, a 1/4-by-3/8-inch suits tiles from roughly 8 to 16 inches, and a 1/2-inch notch or larger is for big-format tile 16 inches and up. The goal is full thinset coverage under the tile with no voids, at least 80% coverage for a dry floor and 95% for wet areas. Pull a set tile up occasionally to check the back is fully buttered; hollow spots crack under load and sound drummy when tapped.

How long before you can walk on and grout new floor tile?

Give the thinset at least 24 hours to cure before walking on the tile or grouting, and longer in cold or humid conditions or with large tiles that trap moisture underneath. Walking on tile too soon shifts it in the still-soft mortar and ruins your flat, even surface. After grouting, wait another 24 to 72 hours before heavy use and before applying a grout sealer to cement grout. Rushing either cure is a common cause of loose tiles and cracked joints, so build the wait into your schedule rather than fighting it.

Should bathroom floor tile match or contrast the wall tile?

That is a design choice, not a technical one, so it comes down to the look you want. A common approach is a smaller, more textured floor tile for slip resistance paired with a larger, smoother wall tile, which also happens to be practical: a matte or textured floor tile with a decent slip rating is safer wet than a glossy one. Continuing one tile from floor up the wall can make a small bathroom feel larger, while a contrasting floor grounds the room. Prioritize slip resistance on the floor first, then choose color and size to taste.