Sheds buildings coops green houses cabins etc we build with 5/8in plywood and 3/4in plywood flooring on all of our buildings the only osb is on the roof the way it should be if you want it to last a very long time and all green treated floor joists also all buildings over 8ft wide have 4by6 skids on them 8ft wide have 4by4 skids and all buildings over 8ft wide have 2by6 joists 8 widespread are 2by4 joists thanks for looking