add second plasterboard to ceiling

[svouts]

What is the best way to add a second layer of ceiling plasterboard with good vibration in insulation for impact sound?

I was thinking to use plastic drywall plugs and attach the second plasterboard straight on the ceiling with a rubber layer in between

 

[tony1851]

Screwing the new board direct to the exiting ceiling, even with a rubber layer, mayl not add much to impact sound insulation.
Really, you need to apply resilient bars to the ceiling, and then fix your (ideally acoustic) board to them.

 

[svouts]

OK I would prefer to avoid it but I think I will add resilient bars.
Mt project is:
1. add directly to the ceiling Tecsound SY50 self-adhesive 2.6mm rubber sheet.
2. 15mm resilient bars
3. basic 8mm light foam carpet underlay between the resilient bars (to support rubber sheet in case of adhesive failure and reduce any reflection of the sound effect)
4. 12.5 acoustic plasterboard

In total i am going to loose 30.1 mm of ceiling height.

What do you think?

 

[tony1851]

What you are proposing to do could well be OK. However, if you are in a flat, for instance,and trying to reduce sound transmission from above, it is not as simple as insulating the ceiling.
You might get flanking transmission from the walls, for example, by which the sound by-passes the work you do to the ceiling.
Unfortunately, one of the best ways to reduce sound penetration is to reduce it at source, rather than trying to build a defence against it. Is there decent underlay and carpet above? If not, is there any chance of adding it?
Lining the ceiling as you suggest will undoubtedly effect some improvement; whether you feel it justified only you can tell but hopefully it does.
If you have noisy neighbours, you have my sympathy.