I have a 2nd story covered deck, single payne windows, sliding door going into covered deck/room and sliding door leading to uncovered deck. Would like to make it more weather friendly. The wood has spaces in them which allow for very cold wind to flow upward, which is not bad in the summer heat. Am a novice at homerepair and such but is it ok to just put some sort of "wonderboard" down followed by peel and stick tile or pergo? Do I need to apply some sort of insulation to the underneath part of the deck? Can't really insulate the walls or anything unless I make the room smaller but I want to turn it into a computer room/guest crash room. Any simple ideas?