A plywood subfloor will bridge any minor waves in the existing floor and leveling compound would help too.
How to level basement floor with wood.
If the uneven floor is due to floor joists that have warped or twisted over time or were incorrectly installed the only way to level the floor is to remove the subflooring and shim the joists.
Make a final check with the level to be sure all the high and low spots are gone.
Place the first sheet into position along one of the walls with the groove edge facing into the room.
Match the scribe bottom to the surface of the floor.
To resurface an uneven concrete slab begin by laying a long straight 2x4 wooden rail across the concrete slab floor.
Then mix a self leveling agent with water in a large bucket and pour it over the surface of the floor.
This will expose the subfloor underneath which is where most leveling problems lie.
Then vacuum the floor with a wet dry vac or sweep it with a broom.
How to level a floor for installing tile before you install file flooring follow the directions above for fixing high spots and low spots in a wood or concrete subfloor.
To level a basement floor start by removing any furniture and appliances on it and then thoroughly cleaning it.
An uneven basement floor can either prevent the completion of a basement upgrade or it can undo your hard work when the tiles crack and water collects it also makes it harder to install flooring in the first place.
Trim as needed and place the next sheet in the first row.
Use a pry bar to pull up hardwood floors one section at a time or unfasten carpet or laminate and roll it up from one end.
Use a squeegee or trowel to spread the self leveling agent around until the whole floor is covered.
Slip shims under the low end of the 2x4 rail until it s perfectly level then use a scribing tool to transfer the.
On the top side of the floor another fix it idea to lay down new hardwood over the existing floor.
Fasten the sheet to the floor joists with 2 1 2 inch screws driven through the old subflooring and into the joists below.
Drive a screw every 6 to 8 inches along all of the joists.