Planning on building a set of outdoor stairs at a cottage that will have a total rise of somewhere between 12 to 15 feet along a steep slope. (Total rise from the cottage to the water is over 40 feet with a combination of ramps and stairs.)
The stairs will be approximately 40 inches wide with open risers and 3 notched stringers.
The stringers will likely be over 20 feet, so I am thinking I would glue up (Gorilla glue?) a stringer that is a PT 2 x 4 and 2 x 8 edge joined (16 footer and 8 footer). The stringers would have a scarf joints at opposite ends and the 2 x 4 would be on the bottom side of the stringer. (The 2 x 8 would be notched for treads).
I can provide midspan support from underneath.
Other ways of doing this?
Thanks