Acoustic insulation Isover RD35 vs Rockwool RWA 45

fifthofwhisky

A stud partition has only a 40mm void so I'm limited in what sound insulation I can use. Found two products, namely Isover RD35 and Rockwool RWA45. Does anyone have experience with these products and know which might offer the best acoustic performance (the RD35 would be 35mm thick and the Rockwool 30mm. I cannot find like-for-like acoustic performance data to compare on spec.

longwalks1

Following with interest, have recently blocked off a doorway with 63mm CLS timber and have Rockwool to soundproof it. Wondering if put it in loose, or cram as much in as possible as will have quite a bit spare


I went with the Rockwool only to bump up the total price of an order to get free delivery

Grenage

For soundproofing you want mass, so get it as dense as possible.

king132

I would think you'd be better off using a good plasterboard like gyproc soundbloc and then filling the cavity with something dense like 40mm celotex

fifthofwhisky

From what I have read it is beneficial to have an air gap and not fill the entire cavity face-to-face with acoustic insulation. It is however necessary to provide a physical barrier (to avoid leaks) so the edges of the studs should seal. One interesting point I read is that very high density (e.g. 100kg+) can reflect sound rather than absorb it.

As far as I can tell, Celotex is primarily a thermal insulator. It might help with acoustics but I doube its performance will match a product designed to reduce noise transmission.

Acoustic plasterboard will help, better if there is space for two layers (one installed vertically and one horizontally) ensuring there are no gaps.

I'm also looking at the sandwich boards with rubber/high-density foam/rubber/plasterboard. These vary in thickness between 22.5mm to 30mm.

Anyway, back to acoustic insulation, it seems that 35mm Isover RD35 might maximize thickness while leaving a small air gap. It would be good to hear from someone who has used this.

I have previously used Rockwool RWA45/RW3 on another application and it was OK, but that was a lot thicker.

fifthofwhisky

Just confirming that I'm going with 30mm Rockwool 60kg rating and leaving an air gap which will increase the effectiveness in terms of noise reduction. I'll put a sheet of acoustic plasterboard (or two if possible) over.