Floor Squeaks Video
Have a floor squeak that is driving you crazy? The floor squeak normally happens when the flooring is not held tightly against the floor joist. As you step on the loose board, it slides up and down on the nail. That is what causes the squeak. If the subfloor is exposed, screw it to the floor joists. Screws won't back out as easily as nails.
Locate a floor joist by driving a nail into the subflooring until you feel the nail hit the joist. Mark that spot, then find the other edge. Once both sides are found, draw a line the length of the floor. Then you can screw the subflooring down along the floor joist. Use 1-5/8" coarse thread drywall screws for the job, spaced about 4" on centers along the joist.