Basement Sound proofing Advise for a referb

[Pupster01]

Hi All

I'm currently spec'ing up to carryout the tanking ECT of my basement home cinema room in a victorian/edwardian Ex Ale house . I've read through the excellent cellar conversion thread and just want some advice on the sound proofing plan i have

The first job will be the ceiling this will have rockwool between the joist to the existing room above for sound deadening and insulation reasons then 18mm plasterboard will then be attached this is intended to extend to 10mm from the walls to allow the membrane to go behind the joint and to keep the ceiling decoupled from the walls keeping noise and moisture transmission to a minium. Joints will be roughly filled in preparation for sound proofing ( this should also keep the dust from migrating round the house if nothing else),

The basement is obviously underground and of brick construction (thus as sounds dead as posible). To this we will be attaching a olroyde membrane which will have a 25mm celotex backed plasterboard directly attached using dot dab adhesive. the membrane should also decouple the plasterboard from the existing walls and provide 10db - 15db of attenuation (i cant find figures for the attenuation the celotex plasterboard) this will then plastered which should seal the wall ceiling joint

following this a second layer of 18mm plasterboard will be going on the ceiling with green glue in-between this will then be plastered ( building regulation require a double skin of plasterboard) .

The hope is that by using a 2 stage construction on the ceiling a stepped joint should be achieved minimising noise transmission paths

My Main aim with the sound proofing is to keep noise out of the room above and the wall adjoining so as not to upset my partner or my neighbours as well as improving the acoustics of the home cinema room.



so people does the above sounds like a good plan?
Is there anything you can suggest to improve on this?
Do you think the use of Acoustic Plasterboard would make a significant difference to the ceiling performance?

all help is gladly accepted positive or negative i only ask that comments are backed up with reasons as there's nothing worse than a response condemning something that cant be substantiated.

[kansashick]

You might consider using acustiblock, soundbreak or similar product mounted using RISC clips and hat channel. This approach virtually eliminates the transmission of vibration (sound) from the board to the studs. It adds a bit of cost but is cheaper than using the higher grades (e.g. QuietRock) of sound resistant board, which are very expensive. (For example, I was quoted prices of from $50 to $250 for QuietRock depending on thickness).

My project is very similar to yours and I achieved a virtually sound proof room using this approach.