sound bloc on top of insulated plasterboard?

[ashthekid]

Hi, this may sound like a silly question but is it ok to have on a new roof structure to have 150mm rafters with 100mm rigid insulation in between, then 72.5mm Kooltherm insulated plasterboard, then battening, then followed finally by 15mm soundbloc?

 

[nod]

Not a silly question 

Absolutely fine and more common than you would think 

If the Batons are simply to carry the SB It would be more entice to use Res bar at 400 centres 

[jfb]

why bother with the plasterboard you aren't using? 75m insulation, battening, 15mm soundbloc?

 

Is it the extra sound reduction?

[ashthekid]

That is true, we could just do 75mm of rigid insulation(without the plasterboard), battening, then the 15mm soundbloc on top of that.

It is for both thermal and extra sound reduction. 

 

The original spec'd plan was 25mm insulation, battening and 15mm soundbloc which I didn't feel was enough in a pitched roof.

[ashthekid]

1 hour ago, nod said:

Not a silly question 

Absolutely fine and more common than you would think 

If the Batons are simply to carry the SB It would be more entice to use Res bar at 400 centres 

Res bars not a bad shout. I didn't;t think of that. sounds quite cost effective as well. and maybe better at sound insulation.

Edited March 16, 2021 by ashthekid

[nod]

I use it all the time on ceilings and walls Cheap as chips and quick to install