Plumbing Soundproofing Question

So I've built the other 3 walls of my room by room in room methodologies and now comes the last and most difficult (BTW these photos dont show the new walls). I've figured out how to get around these pipes so that's not a problem.

They're really loud when the ensuite above is used.

Question do I need to insulate them in anything?

Or by building around them (no flanking points) is that good enough? By way of information, they'll have 45mm thick beams covering them on the theatre side and obviously nothing on the other.

NJ - that is pretty much what I'd planned, well except for the insulation as that takes up too much room....

MrTim - thanks for that I'll look into it. Makes sense, albeit possibly difficult.

Thinking about it, changing the pipe to something heavier might be an option, wouldn't be hard....messy though

Ok So I'll look into some sort of mass loaded vinyl perhaps and a highly dense insulation? is 1inch/25mm enough?

Problem is, putting insulation on the bottom of the pipe bites into my soffit size, which will consequently make the room's second door smaller. I'm going to have to duck as it is.....

Riteo, thanks Ted.

...Hmm off to find a local supplier of a solution.....more fun and games

That sounds awefully expensive....I might try some lagging first....the house has 2 other bathrooms, perhaps a ban during theatre hours would be simplest

Appreciate the help/suggestions

The cast iron pipe itself isn't that expensive - about $100 for 3m.

I've contacted a plumber to see what it'll cost to replace. I think it'll be worth the extra coin....unless he comes back at $100 an hour and 10hours work..

Just to clarify a point, there will be no contact between the pipes and the room in room structure of the theatre. I've devised a way around this. I haven't drawn it in sketchup yet but basically there will be a beam running on 90x90 posts which will sit inside the line of the wall. These will likely become columns...sorry that doesn't explain it very well.

Try again.

1. There will be 3 stud walls sitting in between the engaged brick peirs.
2. These will be connected by narrow (350mm x 2400mm x 19mm) strips of ply
3. Attached to the ply will be the 90x90 posts
4. The beam will sit on top of the posts and the studd walls (with rebates cut for the sections of the engaged peirs)
5. Sitting on top of that beam will be another beam at right angles that goes up round the pipe
6. The new ceiling joists will sit on this new beam. Basically the posts will support a beam that the new joists will sit on - as if I was building a very heigh (2400mm) deck

I'll them insulate the stud sections, put more ply in, then GG then DD. I'll probably DD and GG around the posts as well. My rear speakers and treaments will sit within the sectional studd walls and I'll cover that section in fabric frames and make the post section a column or feature (timbers, lights something)

I'll hopefully get the cast iron replacement, if that is still too loud there is a 25mm lagging product that looks good, you wrap it around the pipe and seal it off with aluminium tape.