You don t want lots of different floor heights or walking in the attic will be difficult.
Best attic floor board.
If your intent is to use the attic for a purpose other than storage you will need to consider a more finished look.
You ll have to construct a wooden frame or sub floor with boards 16 inches apart to provide extra support for the floor.
The decision regarding the thickness of plywood to use for the subfloor in the attic has a lot to do with how you intend to use the attic and it also.
What size plywood for an attic floor.
Be cautioned though that even with insulation hardwood flooring will cause a lot of foot traffic noise to the floor below.
Also if the attic insulation is thicker than your ceiling joists you can raise the height of the joists to above the insulation by attaching 2 3 s to their top edge before you attach the attic floor boards.
Use old boards that are close to the same thickness in a given section of the attic however.
If you ever need to cover them with finished flooring you can always nail down another subflooring before installing tile or hardwood.
Installing attic flooring for light storage only.
Use 1 foot wide boards in pine or spruce to make quick work of putting down a floor.
But best to.