Pre-cut stringers are a good choice to use on a deck because stringers will not need to be manually cut from 2-by-12 boards. Proper measurements from the deck to the ground are necessary to determine how long the stringers for the deck must be. Install a pre-cut deck stair stringer by first measuring and then cutting the stringers to the correct length needed for your deck.
Measure from the top of the decking to the ground with a tape measure to determine the total rise for the staircase.
Divide the total rise, in inches, by the riser height of the pre-cut stringer to determine how many risers you will need.
Count the number of risers you need on the pre-cut stringer and make a mark with a pencil. Use a straight edge to draw a straight line across the stringer.
Trim the stringer to the needed length by cutting along the line you drew with a circular saw.
Set the stringer up to the deck and secure it temporarily with a joist hanger.
Drill two to three holes on the backside of the rim joist, on the deck, into the end of the stringer with a power drill.
Insert lag bolts into the holes you drilled into the rim joist and tighten them with a socket wrench.
Attach additional stringers by following the above steps.
Pre-cut stringers typically have a riser that measures 6¾ inches.
Stringers will not set properly if the ground is not flat.