Boxing in brown soil pipe, anything to avoid?

[richardrich79]

As the question, we have an internal vertical run of brown soil pipe that needs to be boxed in & soundproofed.
Is there anything where contact with the 'plastic' will cause problems?
The reason for my question is our loft renovation revealed a lot of polystyrene in contact with ring main which apparently is a big no-no & in my bid to soundproof the sound of the flush I don't want to store up trouble for the future.
Thanks

 

[muggles]

Above ground installations of brown soil pipe aren't really correct, it's designed for underground use only.

Nevertheless, that's what you have, and you can soundproof it with pretty much whatever you want, there's no insulation I'm aware of that'll attack the plastic

 

[richardrich79]

Thanks muggles, I know about brown for underground and grey for above but my (ex) builder reconed that as it's being boxed in it will be OK which I guess is true.