Installing ceramic tile underlayment is essential when you are installing ceramic tile on top of a wood sub floor. While this is generally accepted as the best way to do things, there are some people that wonder why you have to take this step. Here are some things to consider about why ceramic tile underlayment is necessary.
Tile Strength
The main reason that you need underlayment beneath ceramic tile is because of the strength of the tile. Tile, by itself is fairly brittle. When it is not attached to the proper sub floor, it will crack and break relatively easily. When you provide it with the proper sub floor and set it in thinset, it becomes very hard and durable.
Sub Floor Strength
A wood sub floor moves up and down slightly when you walk on it. Ceramic underlayment is designed to attach to the wood sub floor and make it stronger. When you add this concrete board underlayment to the surface, it will no longer move up and down when you walk on it. Therefore, this gives you a level, strong surface to adhere the tile to. This will make it so that the tile will not crack or break just from having traffic on it.
Source: www.DoItYourself.com
