Pay attention here, I'm holding the tape
measure at the top of the first stair tread. The tape measure is reading
2 - 5/8 inches, which is the exact amount we need to deduct from the
bottom of the stair stringer.
Remember, we have 1 - 1/8 inch thick stair treads and 1 - 1/2 inch
treated lumber that are stair stringers will be sitting on top of, to
deduct off of the bottom of the stair stringer.
I usually do this to double check my measurements. I can easily subtract
2 - 5/8 inches from 7 - 1/4 inches to find the exact amount that I need
to deduct from the top of the first step, but this is just another way
that you can double check this particular measurement.
Split Level Stair Framing