Step 1: Attach the Staircase Landing Beam

Measure the outer beam of the staircase landing and nail it to the sill board attached to the house foundation. Then nail the crossbeam to the outer beam and the support post. Note: The outer beams on the staircase landing are put together the same way as the beams on the main deck.

Step 2: Support and Level

Temporarily support the structure with a board until everything is level. Once everything is level, take a measurement from the top of the post anchor to the bottom of the outer beam. Using a reciprocating saw, notch out support post the width of the outer beam and saw the excess off the end of the post (Image 1). Tip: To make sure your anchor hole is deep enough for the anchor bolt, simply take a look at the drill bit to see how far up the concrete powder appears That should be the proper length (Image 2).

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    Image 1

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    Image 2

Step 3: Calculate How to Cut Staircase Stringers

The two most important terms when designing a staircase are "rise" and "run." Rise is the height of the step, and run is the depth of the step. The numbers used here are the numbers from our example.

• Measure from the top of the decking to the foundation (84")
  
• A good rule of thumb for the ideal rise is 7-5/8". (1/2 plus or minus is okay.)
  
• Take the height of the stairs (84") and divide by the ideal rise (7.625) The answer is 11.016.
  
• Round to an even 11. There will be 11 steps with each one being 7-5/8" tall.
  
• Next, multiply the rise x 2 (7.625 x 2 = 15.25). Subtract 15.25 from 25. The run is 9.75 or 9-3/4".
  

Step 4: Use the Framing Square for Stringer Template

Using a framing square, lay the square down on a 2 x 12 board (used for more support) with the 7.625" mark and the 9-3/4" mark along the same edge of the board. Draw the right angle onto the board formed by the angle of the framing square. Continue down the board 11 times. Take 1-1/2" off of the bottom rise to allow for all of the stair tread boards.

Step 5: Saw The Stringers

Saw the first stringer along the lines made for the rise and run of the stairs. (Image 1). Use a reciprocating saw to make the large cuts and then come back with a jigsaw to cut perfect 90-degree angles. Use the first cut stringer as a template for the other two and a great tip is to position the template so as to saw off any imperfections in the board. Note: A circular saw will not be able to make a perfect angular cut for the stringer, so you'll need to use a jig saw to get the intricate 90-degree angled corners cut perfectly (Image 2).

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    Image 1

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    Image 2

Step 6: Install the Stringers

Install a 2 x 8 base board onto the top of the staircase landing. Attach the outer stringers to the support posts and the inner stringer to the middle of the plate board. Start with an outside stringer and line it up so it is flush with the top of the support board and is lined up in the middle of the support post. Nail into place. Repeat process with outer stringer. The bottom of the outside stringers will eventually be bolted to handrail posts. Place a level or straight board along the top of the first two stingers and position the last stringer so it just touches the bottom. Nail the last stringer through the back of the support board.

Step 7: Install Stair Treads

Install the stair treads using 2X6 boards cut to length. Place the good boards in front of the step and boards with imperfections toware the back of the step. Place two screws through each tread and into the corresponding stringer.