We put a balcony off of the master bedroom, added french doors and now want to put the flooring down. I want something soft to the feet. Toby has plywood as the subfloor. I found a nice outdoor carpet. What do we put under the outdoor carpet to seal the plywood and to prevent any lifting? We already watersealed everything.The balcony has a drop to it to allow for water run off.I know there is some sort of a glue or something? Your advice would be appreciated! Thankyou Toby and Kathy