Leaking shower waste pipe

[randomuser]

Hi, hope someone can help.

I could see a slight leak on the living room ceiling. I cut a hole in the ceiling to investigate and this is what I can see. These are the pipes from the upstairs shower. The leak point on the ceiling corresponds to the black mark on the pipe so I am assuming this is the point where the leak is. I am not sure what to do next. Can something be applied to the pipe to stop it leaking? Can the whole pipework from the top park to the bit on the right where the threads are be removed and replaced? Please can someone advise.

 

[avonmouth]

The leak will not be there but probably higher up around the white nut.Whipe it all dry and then run the shower and feel around the nut for water.

 

[ree]

OP,
Why not disconnect the two white nuts and remove the fitting & examine inside it for blocking?
Why not post a pic of the waste from above?

 

[foxhole]

If you can reach up and tighten the joint at shower waste it may fix it .&

 

[randomuser]

Thanks very much for your posts.

So I have been monitoring since I posted. So from what I can tell:
With my finger/tissue the only wet I could find was at the point in the photo where the black mark is. So it looks like the joint between the two pipes where the black mark is is leaking. I was able to push a tissue (flat single sheet) into the gap that seems to be where that joint is and the tissue was then wet.
I could not detect any other water anywhere else including higher up was I thought maybe it was dripping down and running down on the pipe. But there was nothing. Also no marks of where water might have been in the past.
The water from the shower is draining well and when I shine a light behind the pipe which illuminates the inside is appears clear. So no obvious blockage.
The abount of water that leaks per shower is tiny, not even enough for one drop to fall or hang from the pipe
This is a pic from above, I have removed a small grill bit that catches stuff.

OK so assuming it is that joint where the black mark is, what can I do? Does the whole thing just need replacing? I am assuming that it would not be something I can buy of the shelf so I would get a plumber in for that. Should I try and put a bit of silicone around that joint. Is there a more specific product I can buy to repair it? I could then monitor it to see if it still leaks.

Thanks