How to Prep the Subfloor for Terracotta Floor Installation

What You'll Need
Bond Coat
Corrosion Resistant Screws
Waterproof Membrane
Portland Cement
Cement Backer Board

A terracotta floor is a beautiful and durable tile that can be used in any room of the home. Terracotta tiles are rich with color and are not as cold to the touch as traditional tile, which makes them ideal for kitchens or bathrooms. The first step before installing any terracotta tile is to prepare the subfloor. Preparing the subfloor is extremely important for tile, because any mistake will cause your floor to crack. Fortunately, there are many options when it comes to subfloor preparation. However, no matter which method you use, you need to remove any old flooring before you get started. Because tile is so sensitive, any old flooring would not adequately distribute the weight and may cause cracks. This article will go over each subfloor installation method and their pros and cons.

Step 1- Determine Your Subfloor

The first thing you need to do is to determine whether you have a plywood or cement subfloor. This will determine which methods you can use for your terracotta tile installation. If you have a plywood subfloor, you can use a double plywood subfloor or cement backer board. If your subfloor is cement, you have the option of applying the tile directly to the cement subfloor, or add a mortar bed to the cement. Once you have identified whether you are working with plywood or cement, you can choose which installation method you prefer.

Step 2- Double Plywood Subfloor Installation

If you are working with a plywood subfloor, you have several options. The first is using a double plywood subfloor. A double plywood subfloor is just as stable as using a cement backer board, and it is the ideal method if you are worried about the finished height of your floor. You need to use 5/8 inch plywood for the second layer of plywood. Using screws that are at least 1 1/4 inch and corrosion resistant, fasten the plywood to the framing members. Make sure you walk along the floor and refasten if you hear any squeaks. Then add a bond coat, and finally set your terracotta tile. This application should only be used in areas where there is no moisture.

Step 3- Plywood and Cement Backer Board Installation

If you need to install the terracotta in a kitchen or bathroom, you could use the cement backer board method. First, there is a bond coat layer on top of the plywood, and then the cement backer board is placed perpendicular to the subfloor panels. This creates a sort of grid effect, and will provide superior strength. The backer boards should be placed 1/8 inch apart to allow for expansion and contraction. These gaps should be filled with bonding mortar and finished off with joint tape. Then add a second bond coat on top of the backer board and install the tile.

Step 4- Cement and Mortar Bed Installation

There are two different methods of using a cement subfloor with a mortar bed. The first is applying a bond coat to the cement and then the mortar bed directly on top without any reinforcement. The theory on this is that the cement will provide the necessary structural support for the mortar bed. In this application you need to make absolutely sure that the mortar bed is permanently bonded to the concrete. Otherwise, if that bond fails your tiles will crack. You can also add a waterproof membrane between the cement slab and the mortar bed in areas that are prone to moisture. A second method includes the cement slab, followed by a cleavage membrane, then reinforcing wire, a mortar bed with 1 1/4 inch thickness, and finally a bond coat. If you have any concerns about how level your cement floor is, this would be the best application.

Step 5- Direct to Cement Installation

The final terracotta tile installation option is applying the tile directly to the cement subfloor. This should only be done if you are sure that your cement floor is perfectly level. Otherwise, your tile will crack. One option to make sure the cement floor is level is to use a floor leveler. Floor leveler is a cement-like substance that you mix and pour over the floor to fill in any low lying areas. You don't even need to move it around after you pour it, since it will seek out the low areas and level the floor out. Once your floor is level, you can apply a bond coat and install your tile.