How to Frame Deck Stairs

Stairs are the bridge between your deck and the rest of your backyard, and when built properly, they should feel as solid as the foundation of your home. A staircase that bounces or sways is not just a nuisance; it is a sign of poor structural planning and a potential safety hazard. Getting this right requires careful attention to the relationship between the vertical height of your deck and the horizontal space available for the footprint of the stairs. Done well, your stairs will have consistent riser heights and deep enough treads to be comfortable for anyone walking on them. We avoid the common trap of using generic pre-cut stringers, which rarely fit the specific height of a custom deck. By cutting your own stringers, you ensure the bottom step perfectly hits your landing surface and the top step sits flush with the deck framing.

  1. Nail the Numbers First. Measure the vertical distance from the finished deck surface to the ground, then divide by your target riser height to find the number of steps. Use a framing square to mark these increments onto your stringer stock, ensuring the total run provides enough depth for your chosen tread width.
  2. Test Before You Cut. Use a piece of 2x12 lumber to create a master template based on your calculated rise and run. Cut out the steps on your template and test-fit it against the deck to verify that every step is level and the landing point is correct.
  3. Cut Clean, Don't Overcut. Trace your master template onto your 2x12 pressure-treated stringer boards. Use a circular saw to cut the lines, finishing the corners with a hand saw so you do not over-cut into the structural depth of the wood.
  4. Bolt Down the Ledger. Bolt a 2x6 ledger board to the rim joist of your deck to serve as a secure mounting point for the stringers. Use hot-dipped galvanized carriage bolts to ensure the connection can handle the weight of the stairs and foot traffic.
  5. Secure Stringers Tight. Secure the stringers to the ledger using heavy-duty galvanized framing hangers. Space the stringers no more than 16 inches on center to prevent the treads from sagging under load.
  6. Screw Down the Treads. Attach your tread boards—usually 2x6 or 5/4 decking—to the stringers with two screws per contact point. If your design requires risers, install them first, tucked behind the nose of the tread above.