Installing isolation membrane is essential if you are trying to install ceramic tile over a crack in the floor. If you do not cover up the crack, it will most likely end up cracking though ceramic tile at some point in the future. Isolation membrane will provide some stability under the tile and make the tile much less likely to break. Here are the basics of how to install isolation membrane on the floor.
Step 1 - Clean the Floor
In order to apply an isolation membrane to the floor, you will need to make sure that it is perfectly clean. It will not be able to adhere to the floor if there is anything that comes between it and the concrete. Therefore, you need to take your time when cleaning off the floor before starting this process. If there is any paint on the floor or any other type of finish, you need to take a scraper and use it to scrape off the finish. You should also use a vacuum cleaner to get rid of all of the dirt or dust that is on the floor. Be thorough during this process because it is better to take a little bit of extra time now so that you can avoid problems with your floor in the future.
Step 2 - Apply the Thinset
Once you have the floor completely clean, you need to start applying the thinset. The thinset is the same type of material that you will use to install the tile on the floor. This sets up like concrete, so you have a limited amount of time to work once you start spreading it out. Mix up the thinset so that it is about the consistency of peanut butter and then you are ready to apply it. Take a 1/4 inch notched trowel and use it to spread out the thinset. Make sure that you spread the thinset evenly and deliberately over the entire crack. You want to make sure that both sides of the crack have plenty of thinset on them so that the isolation membrane will be able to adhere to it.
Make sure that the thinset is as smooth as you can possibly get it with your trowel. If it is uneven this will also make the isolation membrane uneven and in turn, the tile will not be level.
Step 3 - Measuring the Membrane
Once you have the thinset applied to the floor, you need to measure for the membrane. You should make sure that you cut the membrane with plenty of room to spare. Take your tape measure and then use it to get the exact dimension of the crack. It is better to add a few inches on the ends of the crack. This way, you can always trim off the excess after you have installed the isolation membrane.