Installing Deck Stairs

Steps can be built in a number of different ways depending on aesthetic preference, but most municipalities have specific codes that must be taken into consideration.

Some terminology that you may encounter when planning and building your deck stairs are as follows:

  • Vertical Rise : Distance between 2 steps which is usually 6 – 7 inch
  • Run – Depths of each tread; can range between 11 to 16 inch
  • Vertical drop – height of stairs from the ground to the deck surface
  • Span – distance the stairs cover from the deck to the foot of the stairs

    1. Mark the position of the stairs on your deck. On the side of your deck, mark the location that the two stair stringers will attach (see Figure A). They are approximately 36 inches apart.
    2. Measure the dimensions of your stairs:

Calculate the Vertical drop from the deck surface to the ground. Then divide this number by 7 to determine the number of steps.

Example: if the vertical drop of your deck to the ground is 33 inches

33 / 7 = 4.7 (round up) = 5 steps with each vertical rise at 6.5 inch

Calculate the run that you prefer. Typically two 2×6\’s is a good choice. Which means the step treads will be 11-1/4 inch deep. So your run is 11-1/4 inch. Multiply 5 (steps) time the run (11-1/4 inch) and you get 56-1/4 inch. This is the span of your stairs.

    1. 3. Mark the post hole location

With a 2×4 and a square, lay the 2×4 on the deck about 2 inch on the outside of one of the stringer marks. Measure out the distance of your span calculation minus 18 inch. Drop a plumb bob and mark the ground. Follow the same procedure for the other stringer mark.

    1. 4. Dig the post holes

At the marks on the ground, dig round post holes and pour concrete footings. Attach the post piers and posts as described in the previous chapters in installing pier foundation for your deck.

    1. 5. Mark the Stringers

Use a square to make out your stringers on 2×12 boards. If the deck surface overhangs the frame of the deeck, factor that into the top step. The other steps should be 10-1/4 inch to allow a 1 inch overhang on each step. The rise measurement in this example is 6-1/2 inch as calculated above.

    1. 6. Cut out the markings

Use a circular saw to cut the stringers. Since a circular saw can\’t get all the way into the corners with a cricular saw, use a hand saw to finish each cut

    1. 7. Attach and secure each stringer

Attach each stringer to the deck frame using an angle bracket. Use lag bolts and washers to secure the foot of the stringers to the support posts.

    1. 8. Build the Stair Treads

To build the stair treads, cut 2×6 boards to span the stringers. If you factor in a 1 inch overhang on each side, cut the boards to 38 inch per this example. Allow 1/4 inch gap between the two boards on each tread. Screw the boards into place with two screws per board per stringer.