Leveling an Uneven Subfloor for Hardwood
- 1). Use a string line to stretch across large areas of the subfloor to check how flat it is. The flatness should be checked in all directions in lengths of at least 8 feet.
- 2). Drive screws into wooden or particle board subfloor to make sure all planks or boards are properly attached. An electric screwdriver or drill with the appropriate attachment can be used to install screws to ensure the subfloor cannot move.
- 3). Hammer any nails into place that are protruding from the subfloor. A floor scraper can be used to remove any debris, such as globs of drywall mud that may be on the subfloor, making it uneven.
- 4). Sand high spots on the subfloor using a hardwood flooring edger fitted with coarse sanding discs. If nails and debris are not removed from the subfloor, sanding discs can be damaged.
- 5). Lay thin sheets of plywood along low spots on the subfloor and attach them to it with nails. The string line or straight-edged board can again be used to test for flatness, following the completion of subfloor preparation.