If your intent is to use the attic for a purpose other than storage you will need to consider a more finished look.
Best attic floor board.
You can install inch plywood or oriented strand board osb in 4 foot by 8 foot panels over existing 16 inch oc joists.
What size plywood for an attic floor.
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.
But best to.
If you ever need to cover them with finished flooring you can always nail down another subflooring before installing tile or hardwood.
You don t want lots of different floor heights or walking in the attic will be difficult.
You ll have to construct a wooden frame or sub floor with boards 16 inches apart to provide extra support for the floor.
Use 1 foot wide boards in pine or spruce to make quick work of putting down a 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.
Be cautioned though that even with insulation hardwood flooring will cause a lot of foot traffic noise to the floor below.
First you ll need to measure the area you want to floor so you can calculate how much wood you ll require.