Many buildings in Europe have tile floors that are 1000s of years old that are pristine condition. In the United States, however, tile floor often crack after less than 10 years. What did the ancient Europeans know about tile that we don’t?
The answer is that Europeans developed what is known as an uncoupling system. The system began with a bottom layer of mortar covered by a thin layer of sand. The tile then was set into another layer of mortar on top of the sand. As the building settled and shifted over the years, the sand separated the tile from the floor below, allowing the tile to float on top, unaffected by the building’s movement. Without an uncoupling system, the tile floors of today move when the building moves. Results can include loose grout, loose tile, and in extreme cases, cracked tile as the floor surface under the tile moves and shifts, especially if the floor is big.
Some people have had decent luck, in the past, by first making sure that the sub-floor was thick enough. They’d apply felt paper, wire lath and a layer of mortar before installing their tile. This, however, was a lot of extra work and took a lot of extra materials to add the thickness to the floor. Now people have started to use a product called Ditra. Using the product Ditra incorporates ancient European concepts and 21st-century materials.
It is very important before you begin any floor tiling project to make sure that you start with a sound floor. Adding the membrane under the tile floor will help to lengthen the life of your new tile floor but only if the floor is structurally sound. If there is too much give when you jump around on your floor that most likely means that you will need to strengthen the floor before you begin the tiling process. Check, whenever possible, the frame work below the floor to confirm that the size and spacing of the joists are correct for the span of the floor.
Second, before installing the tile, you will need to roll out and cut pieces of membrane for the whole floor. It’s okay to use small pieces in areas such as thresholds to make the installation easier. If you’re putting down a heat mat for a radiant floor, install it before the membrane. Snap chalklines for each course of tile before it’s installed to help guide you so that you don’t spread more thinset mortar than necessary. For an installation over a wood sub-floor, use a latex-modified thinset that bonds well to the fabric side of the membrane.
Next you’ll need to make sure to keep your trowel lines going in one direction. This makes it so that pockets or voids don’t form preventing the membrane from bonding properly. Then roll the membrane into the freshly laid mortar and push it out float. When the membrane is in it’s proper position, use either a 75-lb linoleum roller or wood float to press it firmly into the mortar so to establish the bond. Make sure to extract any excess thinset as this will cause the floor to be uneven.
The most crucial point of your project is to make sure that you plan your tile layout for both the best look and the least amount of waste. This is done by selecting the room’s focal point and starting at that location. Remember that once you have laid that first tile there is no going back. So, make sure to take as much time as you need to get your layout right and always remember that the first tile you lay will determine the position of every other tile in the floor.