Install outdoor stairs to a deck or porch by attaching the first and last stringers with L-brackets and the interior stringers with 3-inch decking screws. Follow all local building codes and ensure that the stringers are flush with the top of the deck's joists for a smooth transition.
To attach stairs to an exterior deck or porch:
- Design the stairs
- Attach the skirt boards
- Add support
- Finish the steps
Before building and attaching the stairs, create a plan and design for how the steps will attach. Dry fit the stringers to ensure they are the proper length, and then outline the step pattern and use a circular saw to cut out the stair notches on the stringers.
Mark the deck where the stringers and skirt boards will attach to the rim joist and attach the skirt boards with L-brackets. On the back side of the deck rim, screw three 3-inch deck screws into each skirt board, and then screw the middle stringer to the rim with two 3-inch deck screws.
Using 3-inch deck screws, screw 2 by 6 boards along the back of the deck rim to support the stringers. Attach support along the bottom riser of the stringers and ensure the steps are square.
Nail on the remaining risers and treads, working from the bottom of the steps to the top.