Its not a price thing, its a ive got a ton of 1/2 plywood thing. I can use it elsewhere, but using it as flooring was the first use that popped into my head. I had to ask..thanks for the answer!If you are going directly onto the metal flooring I guess it would be enough. If you are going to lay onto insulation or furring strips I would think the extra thickness of 3/4 would be good insurance. Is the difference in cost for 10 sheets of plywood all that much? I just looked up the price at Lowes. The difference for severe weather plywood is about $4 a sheet.