Preparing a Worksite for Ceramic Tile Installation

Preparation for a tile floor is as important as any step in the tiling process. Taking extra care in the preparation process can save you time, material and aggravation, so follow these guidelines closely. The first steps are to insure the substrate is appropriate for the application. Taking these steps will not only insure the quality of your work, but also guarantee that your flooring will remain in place and free from stress cracks for as long as possible.

In some cases, screeding - a procedure that uses a very dense cement mixture - is spread to level a floor. While this is not a procedure often tackled by the non-professional with care and patience, the finished result can be truly amazing. The next step in preparing for a tile floor is to gauge or lay out the planned flooring area. During this process, it is important to take into consideration any obstacles you may encounter during the installation. These obstacles may include standpipes, drains, doorways, electrical receptacles or floor vents. When preparing for a tile job, it is best to think forward to these potential scenarios and know what to do when they arise.

Consider Substrate Material. When considering an appropriate subfloor or substrate, it's imperative to consider a few factors. Introducing a cement board or hardi-backer style substrate may raise the level of your floor by up to a half inch. Once that is added to the quarter inch height of the adhesive and the quarter inch of the tile itself, you have now increased the height by nearly an inch. This may be a factor when considering door clearance, or thresholds for crossings into other rooms. When considering height increases in bathrooms, an extended drain pipe may need to be installed in certain circumstances to insure proper connection and sealing to prevent leakage.

In applications where height restrictions prevent cement board, thinner materials are available; lauan or composite substrates offer an equally strong bonding agent and are only around 1/8" inch thick. Both these substrates are applied approximately the same way: drywall screws are applied to all four corners of the board, secured tightly, and countersunk appropriately to ensure levelness throughout. This procedure should be followed for the entire flooring area, and seams should overlap evenly over plywood joints. This is done to ensure that no tile is left in the middle of a gap, where stress and traffic can cause the tile to break.

Screeding. Screeding is a procedure most commonly associated with commercial applications, yet in recent years, it has found usage in homes across the country. It is best used in a scenario where a high spot is present and the rest of the floor must be brought up to that high spot to ensure levelness.

  1. Using a moist mixture of sand, Portland cement and lime, rake together everything in a large pan and spray lightly with a hose. Once the mix is sufficiently moist enough to clump in your hand and stay together, you are ready to spread the mixture across your floor.

  2. From the low spot, create a level “ribbon” of sand the length of one wall and even with the high spot. Create another ribbon on the opposite wall, level with the high spot. The two ribbons should now be level to each other. You will use these ribbons in conjunction with a large straight edge to evenly distribute the rest of the mixture across the open floor space.

  3. As you make your way across the open area, using a flat trowel, firmly trowel the screeded area to satin finish and inspect the areas for cavities. If you find a cavity, take a fistful of the screed mixture, and forcibly throw it directly on top of the affected area. Pull your straight edge over the area, and trowel to a smooth finish.

  4. Once you have screeded the entire area, let the mixture sit overnight to ensure a solid working surface that you will be able to walk and work on.

Laying Out the Tile. Gauging an area, or creating a layout, requires a certain amount of patience and savvy.

  1. Beginning with the center of the main entrance to the room, snap a straight chalk line through to the back of the room. Use a square to make sure the line is perpendicular to the door.

  2. Determine the center of the chalk line you just laid. Snap another straight line again, perpendicular to the line already present. This is your guideline, a simple gauge to determine if the floor you are laying is straight.

  3. Start laying out dry tile from the main door into the room, so that a full row of tiles is visible when you enter the room. Starting from the door, lay tiles along the first line you snapped. Use a spacer in between each tile to ensure consistent joints between tiles. You can use the side of another tile or another uniform object as a spacer.

  4. Once you reach the opposite end of the room and can no longer fit a full tile, lay a long 1” thick piece of wood perpendicular to the row of tiles, and tack it in place with a screw gun. Continue laying tiles next to this board, moving across the room in both directions.

  5. Examine the amount of un-tiled space left on the sides of the room, and determine how much you need to shift the rows so that you have equal borders on both sides of the room. Snap a new center line based on this measurement. The intersection of the new line and the board will be your new starting point for installing the tile. The original snapped line can be disregarded.

  6. Examine the area for obstacles. If drain pipes are located in the area, make note of their location in the courses, and determine if an adjustment in the layout needs to be made.

  7. Factor in any space, such as a closet or open cabinet bottom, that may need to be tiled. These can be tricky cuts, so prepare for them early to insure a timely and easy installation further down the line.

Now that you have taken the time to gauge, lay out and prepare your flooring area for installation, you can rest assured that your project will move smoothly towards completion. Should any questions arise, refer to your local home improvement store professionals. Be sure to inspect any beams or hardwood subfloors prior to installing any type of substrate. If the removal of any prior flooring is necessary, make certain that every element of that previous floor is fully removed and disposed of properly.