DIY Guide: How to Properly Prep Your Floor for Tile Installation

Nothing like the satisfaction of a job well done. Standing there, arms at your sides like a superhero, nodding and patting yourself on the back. All of which you’ll surely do standing on your new tile floor. But while tiling your own floor can be a beautiful and satisfying project for the do-it-yourselfer to attempt, it is one that is filled with areas for potential mistakes.

In this two-part series, we’ll walk you through the main steps, including key tools and pitfalls to look out for in your tile install job, as you take a run at prepping, tiling and grouting.

Part one will cover the most important and often the most overlooked step: preparation. Like many DIY/home improvement projects, tiling relies heavily on proper surface and substrate preparation. To say that it is crucial would be an understatement and that’s why it gets its own special part of this series. Part two we’ll go through the meat of how to actually tile and grout a floor.

So let’s jump in and take a look at what you’ll need to start preparing your floor for tile installation, including the tools and some things to look out for when attempting this primary stage of the project.

Should any of this seem out of the realm of possibilities for you, drop us a line and we would be glad to help. Our team of professional installers and account managers have years of individual experience to make your project of installation of tile a breeze!

Large Tile in Living Room

Tools Needed for Floor Tile Preparation

Here’s a quick rundown of tools you’ll need to prep your floor and space for tile installation:

Safety & Comfort

Goggles or Safety Glasses
Knee Pads

For Prepping a Plywood Subfloor

1/4” Cement Board
Backerboard Screws
Saw
Crack-Prevention Membrane

Squaring Room

Tape Measure
Chalk Line
Carpenter’s Square
Hairspray (optional)

Steps to Successful Floor Prep for Tile

Remember, these basic steps apply to all flooring tiles: kitchen tiles, bathroom tiles, mosaic tiles, stone, ceramic tile, porcelain tile and more. In short, if you’re just starting out with tiling, floor tile would be a much better place to begin than would a backsplash, as installing tile on a wall would require even more skill due to the vertical nature of walls, in tangent with the effect of gravity.

No step-by-step instructional is 100 percent exhaustive. Every project is different, and in your own home, you will inevitably encounter something not covered by this or any tile tutorial. But, if you follow these steps, generally, you’ll find success in your project.

So, let’s get started!

Step 1: Prep the Subfloor

If there’s one step that’s the most important, it’s this one. This one is key. First things first, what exactly is a subfloor? It’s a catch-all term for the floor underneath your finished floor. Two primary types of subfloor: wood and concrete. Both suffer from the same tile-killing issue: movement. Wood moves and flexes with humidity and changes in temperature; concrete can move depending on humidity, moisture, soil movement, and temperature.

Pier & Beam House: Wooden Subfloors

Remove any staples and drive down any screws or nails that are sticking up too far. Install a cement backer board to set a good base for your tile and prevent any movement-related cracking of tile or grout.

Backer board is screwed down to wood subfloor using specific backer board screws and mortared down with tile adhesive mortar plywood subfloor. Remember to tape and mortar the joints between the pieces of backer board. Crack prevention membrane is mortared down on both surfaces. This membrane also acts as a waterproofing membrane and is a helpful addition in a wet area, a second floor, or a plywood subfloor application. A notched trowel is used to spread the mortar at a 45-degree angle to the plywood subfloor.

Concrete Subfloors

For concrete subfloors, make sure you remove any old adhesive, and patch/fill any cracks with the appropriate product (check your local home improvement store or reach out to your trusty friends at The Good Guys for tile and installation products. The recommended patch item varies based on the size of the crack to be filled). Use a floor scraper to remove any loose debris. For old adhesives or mortar, this may require some elbow grease and possibly a grinder to remove from the subfloor and allow the new mortar to bond. Floor tiles can be installed directly onto a concrete subfloor.

Whether wooden or concrete, make sure your subfloor is clean and free of debris.

Step 2: Determine Starting Point and Practice Lay Pattern

Laying out your tile pattern, planning for fixtures, cabinets, etc., in advance is critical to minimizing waste (less cuts!) and making the job go as smoothly as possible.

There are many patterns to choose from, though some work better with specific tile shapes and sizes. Herringbone, brick bond, and basket-weave/parquet are very popular in recent years. You should determine this prior to selecting your tile, but if you’re using traditional square tiles, a linear or grid pattern is timeless and easy to install. This is tile laid next to each other, in the pattern you’re envisioning in your mind as you read this. Yes, that one.

Determine your starting point in the room. Typically you will want full tiles in the most visible or focal points in the room, and cut tiles against cabinets or less visible walls in the room. Measure your room to determine the center, and snap chalk lines on the floor to guide your installation. Make sure to leave equal space at either side so you don’t tile up to one side with a full tile and have a partial or cut tile on the other. Every space is different, so take your time and plan accordingly. The goal is to get as many full field tiles down on the floor and leave the custom cuts for around obstacles, under appliances, and against the outside wall areas.

How to Square a Room for Simple Tile Installation

For most simple applications, floor tiles can be laid out in a grid pattern that starts at the center of the floor, so that cuts at the edges of the floor will be consistent at opposite walls. To achieve this, one method is to divide the floor into four quadrants that intersect in the middle of the room. These quadrants should be square to each other, however, this may be an issue in older homes where the room itself is unlikely to be truly square. Don't rely on the wall positions to set up your grid, but rather square it yourself at the center.

Measure one side of the floor, find the middle and mark it with a pencil. Do the same along the opposite side of the floor.
Snap a chalk line across the floor, from one mark to the other. Spray with hairspray to keep the line from smudging.
Measure and mark the middle for the two remaining sides of the floor. Lay the snap line from one mark to the other so it intersects the first line in the center of the room. Don't snap the line.
Lay a carpenter's square at one of the four corners of the intersection created by the chalk line that you laid first and the string. If the line and the string are truly perpendicular, then each will run right alongside one edge of the carpenter's square.
Adjust the string, if necessary, so it is completely square against the chalk line. Once the string is square to the line, snap the string. Spray with hairspray to keep the line from smudging.
Start laying your floor tile, using the center + as your starting point. If you're laying tile, you don't have to leave any buffer space around the edges, as tile does not expand or contract like other flooring materials would.

**When to Not Start in the Middle of the Room**

At times, centering a room is not necessarily the best layout for your floor tile application. You would start from the middle of the room if the space is a simple rectangle or square shape similar to the diagram above, and the only room being tiled. Example, a wide-open square or rectangular room. This could be a dining room or an open bedroom.

In a kitchen, you would not just center the room. You would lay your full tiles at the transition to the larger adjacent room, typically the living room. Then the cut tiles would go against the walls and at cabinets.

In a hall bathroom or laundry room, you would start with full tiles at the door and the longest straight wall in most cases. This is the wall that the door swings in towards. This would put your cuts against your cabinets and behind your commode and against the tub/shower; or under your appliances if in the laundry room. In these areas, the entry and main walls are the focal point.

In a master bath, you would typically start a full tile at the entrance door. Unlike a standard hall bath, many times a master bath’s focal point is the tub and shower side of the room, so put your full tiles against the tub and/or shower and allow the cuts to land at the cabinets. This does depend on the layout of the room.

Whether you decide to begin in the center or at a focal point, chalk guidelines are still a great first step, as they can ensure your final layout is straight and parallel. Practicing with a dry layout of your tile can help you determine what is the main focal point in the room, and the best place to begin.

Floor Prep Step Complete!

Wow. That was a lot of information, right? Is your head spinning yet? Still want to tackle the tiling?! No one could blame you if you didn’t (and we’re here to step in and help).

But fret not, the best is yet to come on your tiling project. As stated earlier, the preparation of your floor is the most critical part of this job. Just like you shouldn’t build a house on a foundation of sand, you shouldn’t start a tile job with a poorly prepared substrate.

But now that you’ve done that great preparation, following everything we’ve detailed, what’s next? How do you move forward on the project?

We’ll get you everything you need, all those answers . . . in Part 2: How to Install Tile Flooring!