I am planning on adding a spiral staircase to my roof, but after preparing the hole for the concrete foundation, I noticed there is this sprinkler pipe 12 inches under the ground which would be directly under where I would like the foundation to be. Obviously I am worried about the pressure of the staircase/foundation breaking the pipe and causing the ground to sag beneath the foundation. I plan on using about 4" of sand/gravel mix at the bottom of the foundation, and about 8" of concrete above that. The sprinkler pipe (as seen in picture) is about 1/2" wide.
I was thinking about how the options I have to resolve this:
a) re-route sprinkler pipe to go around foundation,
b) increase area of foundation to reduce pressure on pipe (perhaps going from a 1'x1' square to 2'x2' square),
c) encase the pipe in something like a steel cover to protect it from damage.
Option A would be quite challenging, so I was thinking of a combination of option B and C. Does anyone have suggestions as to the best way to tackle this? Appreciate it!