About Tile Installation
There are several methods for installing tile floors. We'll show you how to lay floor tile in a bathroom using one method below, but always follow the tile manufacturer's instructions for how to tile a floor, as well as any building codes that apply to your work.
A shower wall tile or bathtub tile install is different from tiling a floor, so even if you’ve completed one of those projects, review the steps for this type of tile installation before you tile a floor.
A tile floor installation will take a few days to complete. In addition to removing any existing flooring and installing the tile, it takes time for the thinset mortar to set and for the grout to dry, so you won’t be able to immediately walk on the floor. Make sure you plan for the time required.
Preparing to Install Floor Tile
The most important step for a tile install is preparing the subfloor properly. For this project, we're starting with a bare subfloor in a new bathroom. If you're removing an old tile floor, then you need to chisel out the old tile and use a floor scraper to remove old mortar. Removing existing tile can get dusty. Protect adjoining rooms, make sure you have good ventilation and wear the correct safety gear such as eye protection and a safety mask.
In an existing bathroom, you'll also need to remove the toilet and baseboards, and you may need to remove the bathroom vanity.
The main thing you're looking for is a level subfloor. If you have any low spots, you can fill them with a leveling compound.
Installing Floor Tile
Before you begin, make sure you have enough tile for the job. Measure your bathroom width and length, and multiply the measurements together to get your square footage. Add an additional 10% so you have extra in case of broken tile or mistakes. Use our Tile Flooring Calculator for a quick estimate.
Thinset mortar is the adhesive that'll hold the tile to the floor. Often, you’ll see it referred to as thinset. We'll also be using thinset to attach a tile membrane to the floor and to attach our tile to the membrane. The membrane we're using for this project is an uncoupling membrane, and it allows for expansion and contraction under the tile without cracking the floor.
For this project, we're using unmodified thinset mortar, but if you aren’t using an uncoupling membrane and are installing your tile onto a cement backer board, you'll want to use modified thinset, which is mortar with a polymer that improves bond strength.
How to Install Tile Floors
Step 1: Cut the Tile Membrane to Size
Lay out your membrane with the fleece side down, and mark the subfloor at the edges of the membrane so you know where to spread the thinset. Use a utility knife to cut around any pipes.
Step 2: Spread and Comb the Mortar for the Tile Membrane
Mix the unmodified thinset. You'll know it's the right consistency when you can draw your trowel through and the ridges just stay standing up. Work one section at a time so the thinset doesn’t dry before you can install the membrane. Spread the thinset onto the floor with the smooth side of the trowel, covering the whole area evenly. Then use the notched side of the trowel to comb the mortar.
Step 3: Install the Tile Membrane
Roll the membrane out and press it down into the thinset using a wooden float. Continue working in sections, applying mortar and then membrane.
Step 4: Waterproof the Membrane Seams
To waterproof the seams, use waterproofing tape. Spread some thinset onto the membrane and embed the tape into it with your trowel, making sure you have at least a 2-inch overlap on each seam. Cover the seams between the membrane sections and the seams along the walls. If your bathroom has finished walls, you can seal along the walls with caulk or a sealant designed for your membrane instead of the tape.
Step 5: Create a Starting Point for Laying Tile
Next, mark reference lines for the tile. Start by measuring two opposite walls and snapping a chalk line between the center points. Then do the same for the remaining walls. This will give you a starting point. You can spray hairspray on the chalk to help it stay on the membrane.
Step 6: Test the Layout for the Tile Installation
Dry fit the tile to check your layout, and use tile spacers to make sure the expansion gaps are correct. Leave a 1/4-inch gap along the outside edges for expansion. Mix tile from different boxes to help keep the color consistent throughout the room. If you find you have small pieces of tile on one end, you can slide the layout to one side to give your edge tile more width. Remember to mark new reference lines if you shift the layout.
Step 7: Prepare the Mortar for the Floor Tile
Mix more unmodified thinset to a peanut butter consistency. Start at the center and spread the mortar evenly, making sure you fill the cavities in the membrane. As you did before, work a section at a time to keep the thinset from drying out before you can lay the tile. Comb the mortar at a 45-degree angle with the notched edge of the trowel.
Step 8: Begin Laying Tile
Lay down the first tile on the reference line in the center of the room, twisting it slightly while pushing down to make sure you're getting full adhesion. Install tile along your reference line, placing spacers between each tile. Every couple of tiles, pull one up to make sure there's full contact with the thinset. If there's not, back-butter the tile — apply mortar to the back of the tile — to get more coverage.
Step 9: Clean and Level the Tile as You Go
Use a wet sponge to wipe off any thinset on the tile surface. Occasionally check for high spots with a long level, and gently use a rubber mallet to even them out. Remember to leave the 1/4-inch gap at the edge of the room. You'll also need to leave a 1/4-inch gap around any pipes.
Step 10: Cut the Tile as Needed
When you need to cut tile, a tile cutter works for simple cuts. You can cut curves with a handheld tile nipper, and a tile hole saw is best for holes. If you're going to be doing a lot of cuts, you may want to use a wet tile saw, which will make short work of the cutting.
Step 11: Let the Mortar Set
Once you've finished laying tile, let the thinset dry for 24 hours before grouting.
How to Grout Tile
Step 1: Apply the Grout
Remove the spacers between the tile, and press grout into the joints with a rubber float and then pull the grout across the lines diagonally, removing the excess. Wait about 20 minutes and then wipe the grout lines with a wet sponge and clean water.
Step 2: Let the Grout Set
Once the grout is in, you should typically wait 72 hours to walk on the floor, but check your manufacturer’s recommendations for specifics. You can use a grout haze remover to remove any haze left on the tile surface.
Step 3: Finish the Tile Floor Installation
Apply silicone sealant to the expansion gaps. After three weeks, you can apply grout sealant to help protect the grout. Install your baseboards and quarter-round molding. Install transition strips as needed to cover flooring seams when going from one room to another, especially from tile to another type of flooring.