Conservatory roof & waste pipes

[alanclarke_1]

I have a conservatory roof that has a soil pipe and 2 smaller waste pipes that come through.
The builders have boxed the pipes internally to make it look good, but they have used some kind of adhesive tape that looks like lead to try and make the holes for the pipes waterproof.
HOWEVER, the conservatory not only smells of mouold but the box around the pipes is getting mouldy and damp.
I have tried to look at the flashing from a bedroom window but cannot see anything obvious.

What is the best thing for me to do? should I just replace what is there or should I try another way of making it waterproof?

HELP

 

[Mw Roofline]

Is this a polycarbonate conservatory roof or like a lean to felted type roof?

 

[alanclarke_1]

It's a polycarbonate roof

 

[^woody^]

Either way the boxing needs replacing.

Rip it out, check and repair as necessary the seal to the stack/roof (or waste pipe/stack), and only when the problem has been repaired, then replace the boxing.

You may like to use some ply and brass cupped screws for the boxing to allow easy removal in future