Make sure you apply a cementitious flooring leveler you can nail through later.
How to level floors for hardwood installation.
A plywood subfloor will bridge any minor waves in the existing floor and leveling compound would help too.
Hardwood floor installation can be slowed by an uneven subfloor.
If the floor is uneven lift up the board until it is level so you ll know how much flooring compound you ll need to even it out.
Pound nails into the subfloor with a hammer and set screws slightly below the surface of the subfloor with a screwdriver.
Remove any obstacles from the floor.
How to level a floor for installing hardwood before you install hardwood flooring follow the directions above for fixing high and low spots in a wood or concrete subfloor.
Before installing hardwood floors use a straight edge to find the humps and dips in the subfloor.
On the top side of the floor another fix it idea to lay down new hardwood over the existing floor.
Clean it well with a wet dry vacuum.
If the area is very large use a long straight 2 in 4 in 5 1 cm 10 2 cm board and set your level on top of it.