How to Install a Deck Ledger on a Bay Door

Install ledger boards -- lengths of 2-by-6 or larger pressure-treated wood -- on either side of the bay door, fastened by lag bolts to the house rim joist resting above the foundation.

Pour concrete footings per your deck plans, and top them with 6-by-6 posts and post-beam caps. With the help of an assistant, lift your beam, typically made of doubled or tripled 2-by-10s or larger dimensional lumber, in place on top of the posts. Nail post-beam caps to the beam to hold the beam in place atop the post.

Run single joists, typically 2-by-6 or larger, from the ledger to the top of the beam except in front of the bay door. Hang the joists in joist hangers as specified in your deck plans, typically 16 inches on center. On either side of the bay door, run double joists hanging from double joist hangers to the top of the beam.

Double your 2-by-6 lumber to create a header running from one doubled joist to the other just in front of the bay door. Face-nail one piece of lumber to the other. Nail the header in place with galvanized joist nails through double joist hangers. Run short joists from the header to the top of the beam. Cut and clamp in place a deck rim joist to cover the ends of the regular and short joists. Nail the joist ends to the rim joist with joist hangers.

Bevel both ends of two short pieces of 2-by-6 at 45 degrees to create blocking on each side of the bay door between the double header and the double joist. This creates framing that fills much of the void between the curved bay door and the rest of the H frame. Nail the blocking to the outside of the header and the doubled joist with 45-degree-angle joist hangers.

Dry-fit deck boards so that they touch the curving sides of the bay door. Scribe the boards with a pencil compass so that they follow the bay door’s arc. Remove the scribed boards and cut the scribed shape with a jigsaw. Replace the deck boards around the bay door and fasten the boards to the joists below. Complete your deck by installing the deck boards on the main rectangle of the deck, as well as the posts, railings and balusters.