Introduction
I am re-purposing a room from a kitchen to bedroom. The room has a concrete-block built wall through which cast iron water pipes pass.
Here is the approximate schematic
neighbor | p | my room
| | is a single concrete block, and the p is the pipe located inside it.
Whenever the neighbor uses the kitchen pipe, there is a hissing noise in the pipes. Closing the pipe produces a distinct "thud" sound.
I was considering:
- demolishing a part of the wall (one side of a single block) to allow better inspection
- acoustically insulating the pipe with some wrapping material
- green gluing the entire wall
The problem with step 3 is that I don't have much space for the additional layer on top of green glue because I have windows to go up to the wall, leaving very little space on the window frame. 2 cm would perhaps be possible.
Even if the window would not present a problem, I would also not like to lose too much space of the room.
============ <- wall with pipes
w <- window
w
w
The wall concrete blocks are covered with 10-sand:4-lime:1-cement mixture (type K mortar equivalent), looking something like this:

I might be able to get additional space for green glue by ripping that layer off.
I have a good neighbor and it might be cheaper to arrange changing the pipes. However, demolishing his kitchen tiles to get to the installations is most likely out of the question.
Question
- How can I acoustically insulate the cast iron pipe with some kind of wrapping material?
- How can I acoustically insulate the room wall through which the pipes pass efficiently with just an inch or inch and a half to spare?