Oftentimes the terms "flat" and "level" are used interchangeably; however, in the world of tile floors, they can mean very different things. Let's talk about what a flat floor is versus what a level floor is and why all that matters. According to the CTEF, "Flat means no significant high or low spots. In the tile world, the word 'flat' means that the surface does not have any significant high or low spots and will yield a smooth tile installation with no lippage between tile edges. But how do we determine if the floor is flat enough and what is used to make this determination? "In the tile industry, this tool is known as the ten foot straight edge which is usually fabricated of magnesium or aluminum. It can be an “L” shape or a rectangular box." If a floor is not flat, then there are a few options. The first option is to grind the floor down to a flat surface. If you choose to do this, you'll want to ensure you're capturing the dust and using an OSHA-approved method. The second option is to use a patch material. Then finally, you could opt for a combination of the two. Now, in relation to our industry, "level" has quite a different meaning. According to the CTEF, "A level floor means it is parallel to the horizon. A level surface needs to be parallel to its perfectly horizontal plane. In order to determine if the substrate meets the required level plane, we again use the 10’ straight edge with the spirit level placed on top of the straight edge." Whenever you are working on tile installations, make sure you are clear with your customers on the expectation of a level or flat surface. If you promise a level surface when you really mean flat, it could be a costly mistake. As always, our team of tile experts are always here to help answer any questions you may have. Stop by any of our nine South Florida locations and we'll be happy to help with your project from beginning to end.