For the deck frame, including the ledger board, rim joists, and posts, make sure you use pressure-treated wood which is designed to withstand rot. The proper use of waterproofing flashing is also integral to the structural soundness of an attached deck. Without flashing, the wood is vulnerable to decay, rendering deck-to-house joints dangerously loose. Here are the steps for attaching a deck, depending on whether you’re working with a new or old one.