How to Attach Railing Posts to Deck Framing. When homeowners and DIYers build a deck, they often fail to attach the railing posts to the deck framing securely. A secure method of attaching railing posts to a deck is to notch the post at the bottom so it fit snugly in the space between the two outer floor joists. The posts are then held in place with screws. Watch this video to find out more.