The roof decking would be the layer of plywood or O.S.B. nailed on the trusses or rafters. Roof decking is usually seven/16” and comes in 4’x8’ sheets. When you’re tearing off previous roofing, the roofer can try to look for destruction that needs to be fixed after the deck is https://roofers-in-joliet10863.wikigdia.com/6404960/an_unbiased_view_of_roof