If you're lucky enough to be there when they have it, there is no other way to go. Boeing surplus (Kent) from time to time will sell 4'x8' sheets of 5/8" honeycomb graphite composite sheeting (the sheets were $15 a piece 4 years ago). Don't know whats wrong with it but ask me if I care! A whole sheet must weigh all of 35-40lbs and is strong as steel. It takes a little more prep work to lay down though. I countersunk the screw heads in mine. First you have to drill throught the top layer only, take a nail and clear out any adjacent cells and fill it up with epoxy. After the epoxy sets up your free to drill your hole and countersink as, necessary. I put indoor/outdoor carpeting over the top of mine, but will probably change to something else in the future. doesn't really matter what you put on top of it. Advantages are it will never rot, ever - will outlast you even if your 16! you can drop a 50 lb anchor on it (by accident) without breaking a whole in the floor, and it doesn't squeek like wood. Won't swell when wet or shrink when dry.

Good luck!