Of the two most common subfloor materials builders often debate which is best.
Best attic subfloor.
The most common uses are as sheathing in walls flooring and roof decking.
An attic conversion is a great way to expand your home s living space but best to leave the work to a licensed contractor.
Osb oriented strand board is a different form of sheet material.
The wood should be at least 5 8 inch thick to handle a heavy load.
Plywood or chipboard is the least expensive option for storage flooring.
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 depends on the spacing of the ceiling joists.
Weight concerns if you do have an existing walk up attic with traditional floor framing the principle concern when converting the space into a living area will be weight.
The best you can hope for is perhaps to lay some thin plywood platforms down over the bottom truss members and use them to store lightweight items.