Originally Posted by ponch37300
.... I really don't want to carry 3/4" tongue and groove osb up three stories if i don't have to. Can i put another layer of something over the 1/2 osb and screw it down staggering the joints and be ok to lay laminite flooring? Any advice on this is much appreciated. Thanks
First off, you don't have to lug any plywood up, if you have it delivered and boomed in (assuming that there is a location for it to pass-thru).
Second, consider using a 3/8" plywood. Glue down all areas. Shim low spots up to a reasonable level, with cheap roof shingles, placed under the 3/8" ply.