Reducing sound through party wall, which insulation?

[Ian H]

2 kitchens back onto each other either side of this wall:

I want to reduce the noise and plan to build a frame from 2x2, spaced 50mm off the wall, fit a full layer of 50mm acoustic slabs behind it then a further layer between the wood.

I went to get some Rockwool RWA45 today but was told that that will reduce noise but it’s not specifically for sound. They recommended this but I couldn’t see its weight per meter:

Can anyone recommend a product?

I’ve seen Rockwool RWA45, RWA3 and Rockwool Sound Insulation Slab (which sounds ideal)

 

[Ian H]

I had a read up today and chose Rockwool Sound Slab, seemed heavy at 60kg/m3.

So now I plan on actually doing the job.

Where I fix onto the walls at the sides should I put rubber washers between my wood frame and the brick to seperate them? Same for into the joists at the top?

 

[Ian H]

I made the frame tonight. Daughter pulled down the first 6” of ceiling and mortared all around the joists and filled any holes, then we made the frame and fixed it to the ceiling joists through some thick rubber that was a bandseal I had that was missing it’s clips.

Had to stop because we didn’t have a 6mm masonary bit to fix the sides.

 

[GavS]

FWIW I did something similar on a party wall and my experience suggests/was:

• The soundslab you have is def better then the acoustic roll which I don't think is dense enough in this application.
• I used foam tape (resilient foam/strip) around all perimeter timber to try to de-couple a bit from the brick/floor/joists - your rubber might achieve similar - might depend how solid it is.
• I also heavily caulked around all perimeter timber with AC50 before boarding (on the understanding that any gaps, e.g. between timber and the wall would allow sound through and detailing is important).
• Fit soundslab or rock wool good and tight between studs on the same basis - i.e. any gaps will allow sound through.
• Board with acoustic plasterboard if you can/don't mind - it is denser than standard for same thickness.
• I AC50'd plasterboard joints and perimeter as well - not sure this was necessary but no harm done.
• I used a single layer of PB because I was trying to limit overall thickness of the studwall and just stopped at that but in reality another 12.5mm would not have made much difference to thickness and may have improved soundproofing even more. If I did it again I would use two staggered layers room permitting.
• I also put rockwool in the ceiling void between joists on the basis that this was still party wall.

Effect-wise I would say my approach muffled normal tv and talking type sound from a level where I could hear it without trying to having to tune in to pick it up. So basically made the noise much less intrusive.

 

[SFK]

Ian, not noise related...

What Are you planing to put / hand on that wall?
If you are putting a TV, or cupboards, you should consider putting some wood where the screws will go between the studs as fixing points.

SFK

 

[Ian H]

Ian, not noise related...

What Are you planing to put / hand on that wall?
If you are putting a TV, or cupboards, you should consider putting some wood where the screws will go between the studs as fixing points.

SFK

She wants a bare wall finished something like this:

I think that would be MDF so I’m not sure if I should put the blue plasterboard up first or straight on with mdf?

This is where i’m at as of now:

I’ll use the AC50 you recommend around the timber and add some more slab in the ceiling against the party wall The bathroom is above so I will go fully under that to muffle fart noises

 

[freddiemercurystwin]

2 layers 15mm SoundBloc would be advantageous. Don't forget the staggered joints.

 

[Ian H]

2 layers 15mm SoundBloc would be advantageous. Don't forget the staggered joints.

Is there a better product than the blue boards? I put them in the alcoves at my house and they don’t seem to do much.

 

[Nige F]

2 kitchens back onto each other either side of this wall:


Can anyone recommend a product?

I did on your other post. In plastering forum D'oh.

 

[jeds]

2 sheets 15mm dbcheck board is standard spec. You will get a slight improvement of you fix the boards to resilient bars. I would also squirt acoustic foam in every joint around the stud framework. The rule is 10% gaps allows 90% sound transmission.

 

[Ian H]

I did on your other post. In plastering forum D'oh.

This one I can loose 4” but the other needs to be as thin as possible

 

[rideforever]

Sandwich construction is best because it takes out different frequencies of sound, and causes the sound to refract and lose energy.

I would try using :
blue board + foam + high density rubber membrane (link below)
or
blue board + woolroll + high density rubber
or
double blue board + high density rubber

.. https://www.noisestopsystems.co.uk/shop/floor-soundproofing/barrier-shield/

Rockwool never looked to me like it would do much.
Basically use 3 different materials preferring high density ones as they block out low freq sound which are harder to block.

Would be good for someone to do some testing.

A lot of acoustic products say something like -30db but then it says for impact sound, which means like stilletos on the floor. Which is much easier to block than airborne sound.