Stud wall for soundproofing

[msmsm]

Hello,

I want to build a new stud-wall in my bedroom against the single brick party wall I share with my neighbours, to cut down on TV and talking noise, as this seems the best way to tackle this problem.

I have searched a fair bit on this topic and just want to check I have everything covered to do this job....

1) What size wood for the stud work? I am thinking 2x2 - can I use smaller or do I need to go bigger?

2) Attach a stud beam to the ceiling joists and the floor a few cm away from existing wall so there is no contact. Put some uprights in for the plasterboard to attach to. A couple of questions here:

a) How far away should the stud wall be from the current wall.
b) Should the floor beam be attached to the floorboards or the joists?

3) Fill the stud will some high density mineral wool. I guess I want to compact it as much as possible - does it matter if this touches the existing wall.

4) Place a layer of 18mm plasterboard onto the stud work. Fill around the edge and joins with silicone sealant (to allow movement)

5) Place another layer of 18mm plasterboard on the top with the joints staggered. Fill around this and tape ready for plastering?

I guess I also want to fill the floor void with something. Will mineral wool work for this too? The floor void is actually above an alley way. Would mineral wool still be suitable or do I need something that will not absorb water moisture in the air? If so what should I use.

Thanks for any advice. I do not normally take on jobs like this but I have a friend who is willing to help, I just want to ensure I have the right idea before we start.

Matt

 

[Deluks]

2x2 or 3x2 flat side out would be fine.
As far away as possible for performance but realistically a minimum of about an inch away.

Use a noggin between each upright.

Only a lightweight wall really so can screw into the floorboards, although lifting the boards for future maintenance might be an issue so cutting out down to the floor joist where the framework will go, would be wise.

Min wool can touch without transmitting any sound, don't over compress though, aim to get the right thickness for the space.

18mm plasterboard?? couple of layers of standard 12.5mm will suffice, unless you plan on doing the whole house and bricking up all your windows as well.

Buy acoustic sealant, not silicone.

Floor the tricky one, you'd probably be alright with min wool but you should have a polythene barrier on the room side, with no gaps. So meticulous taping down and wrapping under the joists might be in order.

Or you could use min wool batts and 'christmas present' wrap them in poly and tape up tight, before wedging tightly into the space.

 

[msmsm]

Thanks for the help. I need to see what is in the floor cavity already. It is boarded at the bottom with wood and there seems to be some material above this wood, but I can't see from the bottom what it is. It is a Victorian house, so it could be anything....

If there are gaps where my joists go into the party wall what should I fill these with? Is a ready mix pointing type material ok considering it will be in contact with the wood?

Matt

 

[Deluks]

Yes, or a can of expanding foam.