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.
Plywood is made with three or more layers of thin wood glued together with the grain alternating. It is typically made in 4-by-8-foot sheets, although longer panels are available for special purposes. It is a flexible, durable, inexpensive covering for roofs because each panel will cover 32 square feet.