John Sayers' Recording Studio Design Forum Archive

50mm Rock-wool and 50mm Semi Rigid fiberglass boards are about the same price per m2 here in New Zealand although semi rigid sheets will cut to size better for me due to starting sheet size.

Any benefit in using one or the other? – just go cheaper of the two?

I am using the inside out wall system, the insulation is going in a 66mm stud cavity, should I put it flush to the plasterboard at the back or flush to the front of the stud leaving a 16mm air gap in between the insulation and plasterboard – common sense tells me flush to the plasterboard to help with surface vibrations.

If one of the pro's could step up and let me know

Thanks

JG

Anyone have a comment or any experiance with this?
Thanks
JohnG

They are acousitcally the same in this application

If you are putting no inner leaf then it makes no difference. Snug it against the wall if you wish.

Andre

Perfect, thank-you
JG

What is BEHIND your wallboard - if there's insulation between inner and outer leaf (and there should be) hopefully those batts will damp your innermost leaf. If that's the case, you'd get slightly wider band absorption by putting your inner batts (the ones you're asking about) to the INNER edge of the studs. (flush with the inside edge of the frame)

If you do NOT already have insulation between the inner and outer leaves, then you may HAVE to place the batts against the wallboard for damping.

Another possible way would be to get some standard fluffy house insulation and place THAT against your inner wallboard, then the rigid batts trapping the softer insulation against the wallboard; this would still give better absorption than having the rigid batts touching the wallboard, but wouldn't cause you to lose damping of the wall panels... Steve

Hi Steve,
Yes there is batts behind this plasterboard but in some cases it does not touch due to the airgap I left and the angle the walls went in at.

I actually attached the insulation to the existing walls as it was easier to do it that way.

I think I will try "noise control blankets", it is a high density fibreglass product we have downunder that has slightly better specs than rigidboards according to the specs but is not quite as "rigid" - kinda compromise to get that absorbtion and vibration stopping I hope.

JohnG