Rockwool slabs for 4x2 CLS

[23vc]

Got a 4x2 CLS stud wall to insulate, board, skim etc. Will use the rockwool acoustic/rwa45 slabs/knauf acoustic slabs. The 100mm size of these will just about manage in the 89mm space, right? While since I’ve done it. I’ll pack out with strips of plasterboard if not.

 

[noseall]

Got a 4x2 CLS stud wall to insulate, board, skim etc. Will use the rockwool acoustic/rwa45 slabs/knauf acoustic slabs. The 100mm size of these will just about manage in the 89mm space, right? While since I’ve done it. I’ll pack out with strips of plasterboard if not.

I don't use much mineral wool, but it is harder to compress than fibreglass. The difficulty will be getting the sheet to behave whilst you get the first couple of screws in. Not easy. I think strips of plasterboard may be essential.

 

[23vc]

What do you put in stud walls?

 

[noseall]

What do you put in stud walls?

For acoustic or fire?

 

[23vc]

For acoustic or fire?

Acoustic

 

[noseall]

Acoustic

There are probably more user friendly acoustic versions out there. We look foe ease of use as well as cost. It gives off very fibrous dust.

 

[23vc]

There are probably more user friendly acoustic versions out there. We look foe ease of use as well as cost. It gives off very fibrous dust.

Cool, I’ll use whatever people suggest, doesn’t have to be the stuff I mentioned

 

[Deluks]

The rockwool should compress 11mm.
If you get the very dense acoustic stuff then that hardly has any give in it, but RWA45 will be ok. The number refers to the weight per cubic metre, which indicates density.

 

[catlad]

75mm acoustic or 100mm packed out, there is a significant difference between normal loft insulation and rockwool.

 

[Tigercubrider]

In an ideal world, you don’t want the rockwool touching the plasterboard.
Also, ideally, double skin the plasterboard with staggered joints. Use filler when the first layer is done, so you have two distinct layers

 

[23vc]

Cheers all

 

[Deluks]

In an ideal world, you don’t want the rockwool touching the plasterboard.

It shouldn't make a difference really. Extra plasterboard will help though. 2 layers of standard PB will trump a single layer of the acoustic stuff.

 

[23vc]

I’ve never used the acoustic boards, as I’m a wimp and like to work with 6x3s.
The most success I’ve ever had was a combo of rwa45, metal resilient bars and normal boards. Made a very noticeable difference

 

[Deluks]

I’ve never used the acoustic boards, as I’m a wimp and like to work with 6x3s.

At about 40kg each, I don't blame you.
Gyproc plank is another good option, 19mm and easy to handle at 8x2