We spent two and a half weeks fixing a 12 foot high deck that had been standing since the 80s. The main supporting beams had rotten, and caused the joists and many floorboards to do the same. We built a temp wall to support the salvageable joists, and cross braced the support posts. We then removed all the floor boards, most of the joists and the 9"x14"x20' rotten beams, as well as the posts that supported a small roof. We then rebuilt the deck.