If you need to bring down your subfloor you can try either a hand plane or a power sander.
How to fix a low spot in a wood floor.
An underlayment is a thin layer of material sandwiched between two other materials.
Use an underlayment floor leveler or floor patch product to fix low spots in a wood or concrete subfloor.
This requires using a laser level to pinpoint the low areas and attaching the shims working on bare joists above a basement or crawlspace by gluing and screwing them to the joists.
Set the front end of the saw s flat blade plate on the damaged board with the blade held up off the surface and pointing in the same direction as the length of the floorboard.
If you have a drum sander on hand this can level out any bumps in the subfloor but you need to have a steady hand to control this.
High spots and bumps in subfloor.
It s used to help insulate absorb sound and reduce wear on your floor.
Start the saw and lower the blade into the wood.
It can also serve as a vapor barrier.