Deck Building Guide: Footings, Ledger Boards, and Framing Essentials

Credit: mjpyro

With planning complete, clear the deck area and mark the perimeter using batter boards and string. Verify square corners with the 3-4-5 triangle method: measure 3 ft on one string, 4 ft on the other, the diagonal must be 5 ft.

Marking the Deck Area

Remove sod within the footprint plus 2 ft extra. Reuse sod elsewhere—water daily. Lay landscape fabric and gravel if weed suppression is desired.

Attaching a Ledger Board

For decks attached to the house, fasten a ledger to the foundation with expansion bolts (concrete) or through-bolts/lag screws (wood). Flash with aluminum to prevent water intrusion. Position the ledger 1.5 inches below the final deck height to account for decking thickness. Do not attach through siding—cut a pocket for the ledger.

Locate and Dig Footings

Credit: mjpyro

Footings must extend below the frost line (typically 18-24 inches). Dig holes twice the post diameter. For buried posts, add gravel, set post, plumb with a level, and pour concrete. For above-grade footings, use Sonotubes with J-bolts embedded for post anchors.

Attaching the Frame

After concrete cures (24 hours), attach rim joists to the ledger and posts. Use a level and string to ensure straight lines. A slight slope away from the house aids drainage. Beam-to-post connections: through-bolts with washers, or rest beams on posts with added 2x6 supports. Finish with the end rim joist to complete the rectangle.

Credit: mjpyro Credit: mjpyro

The frame is now ready for decking, stairs, and railings.