1 Algorithm based on impact on opinions over time - and Wikipedia. 2  Top ten most significant in history puts Jesus in the number one spot.  The list also includes Muhammad, Lincoln, Hitler and Shakespeare.
Plies vary in thickness from 1.4 mm to 4.3 mm. The number of plies depends on the thickness and grade of the sheet but at least three are required as the minimum odd number of plies. Roofing can use the thinner 5/8 (15 mm) plywood.
Roof sheathing is typically about 1/2 inch thick. Builders love plywood for its water resistance, structural stability and low cost. They also love oriented strand board, though. It costs even less and is comparable to plywood on the other two counts, and they increasingly prefer OSB for roof sheathing. Either is an acceptable choice in most jurisdictions.