Show Pan Access?

[Water_Gremlin]

I believe I have a leak in my shower pan drain in my master bedroom shower. On the outside of the house water is dripping down the wall where the drain pipe would parallel. I have read about the plumbers putty repair and how to go about this problem. The problem is I have no access to the bottom of the show pan. There is another bathroom directly underneath the suspected leaky shower pan drain though. Keep in mind I have never tackled a job like this and I feel like I am walking in the dark, but I think this will make more sense when I have access to the bottom of the pan.

So it appears I will have to cut a hole in the ceiling above leaking shower drain. My question is, how do I go about cutting this hole, and how do I keep from cutting other piping and any possible wires in the immediate area? How do I repair the hole in the ceiling once the job at hand is completed? Any help would be highly appreciated.

[LazyPup]

The ceiling in the room below is most likely made out of sheetrock.

The safest way to cut the sheetrock is by means of a hand sheetrock stabsaw. Working carefully you will be able to feel if the saw hits any pipes or wires inside the wall before it has enough force to cause physical damage.

If you carefully cut a square access panel out from joist to joist you will be able to use that same section of sheetrock to repair the hole, then all you will have is the four edge seams to get a perfect fit..

see the attached illustration.....