Replacement of a plywood subfloor; if you build a shed, make sure you don't place exterior walls atop the subfloor, because sometime in the future the need may arise to replace the subfloor, and if the walls are atop, removal of the subfloor will be most difficult, requiring the sawing or cutting around all the walls to remove the subfloor.
SEE SHED FLOOR REPLACEMENT PART 2 • Shed Floor Replacement - Part 2