Will a solid brick or cavity wall have better sound insulation?

[Thomas Parish]

I am converting a single detached property into a semi-detached by building a party wall directly through the middle.

I have two options for this;
1) Build a solid brick wall, 215mm thick, with plasterboard to each face.
2) Build a cavity wall consisting of two 100mm 3.6n Block wall separated by a 100mm cavity with Rockwool Soundboard within it. Again with plasterboard to each outside face

Can anyone please advise which will achieve the best soundproofing, and perhaps point me to an online resource that shows this.

Intuitively I would say Option 2, but keen to understand more detail.

Thanks

 

[tomfe]

http://www.robustdetails.com/the-handbook/selecting-your-robust-details
Easiest it to follow what's already been approved.

 

[Thomas Parish]

Thank you @tomfe that's a really helpful website.

Any comment on the relative acoustic performance would be appriciated.

 

[23vc]

Single skin block but with resilient bars behind the plasterboard screwed to battens with more rock wool in between battens would be even better. You'd be surprised how effective the resilient bars are

 

[^woody^]

The OP may be surprised how effective 7n blocks instead of 3.5, and a normal air cavity will be ... instead of insulation to transmit sound and a complicated resilient bar system.

 

[endecotp]

The details at junctions with floors, walls etc will be important too.