Subfloor Prep: Using a Multi-Disc Sander or Buffer
For glue-down installations and those using mechanical fasteners shorter than 1 ½", the subfloor should be flat to 3/16" within 10 feet or 1/8" within. fix feet. Here is the basic but effective test. Using a long, straight edge set on the subfloor, lightly drag it across. Because the guidelines describe the tolerance.