I used regular pressure treated plywood from home depot, I know I should have used marine grade ply, but it is way to pricey. I don't wanna dump too much money into the boat (truth be told, it's not big enough for me. I'm 6'8 250 lbs) it's just something to get up and down the creeks in for now. All the pieces are removable, I cut them precise enough that they hold in place. Its an easy, cheap diy project, I spent 30.00 on the plywood and 2 1/2 hours making cuts and dropping it in.

My neighbor (the wise old man next door, lol) recommends I put styrofoam under the flooring, what do you guys think?