Nye

I'm about to build internal stud walls in my house and want to get the best acoustics I can out of them. I'm not sure what to fill the void with though - do I fill all 100mm with mineral wool? Do I fill half? Do I fill half with dense mineral wool and the other half with lighter mineral wool? I read conflicting things on here - any advice? Current plan is: 2 layers of 12.5mm acoustic plasterboard attached to 75mm studs at 300mm centres on a 100mm base plate creating a void - fill to be decided) (with a rubber layer underneath the baseplates and between wall plates and the wall) Staggered (for decoupling) 75mm studs on the other side at 300mm centres 2 layers of acoustic plasterboard

Thanks all! Having read everyone's feed back I think I'm going to avoid recessed ceiling lights and move the vapour barrier closer to the interior. So it might look more like this: 1. Roof tile 2. 25 mm Battens 3. Breathable membrane draped 10mm 4. 15mm air gap in 175mm rafters at 400mm centres 5. 150mm rockwool slab insulation between rafters 6. Tecsound 10 mass loaded vinyl 5mm 7. 50mm battens (perpendicular to rafters), space between filled with 50mm rockwool slabs 8. Vapour barrier 9. 50mm battens (perpendicular to last layer), space between filled with 50mm rockwool slabs 10. 17mm resilient bars (perpendicular to last layer) to create service layer, non ventilated air gap, and decoupled ceiling 11. 2 layers of acoustic plasterboard (25mm total) 12. Skim coat One more question though - rafter specific insulation is incredibly expensive compared to normal rolls of insulation. Knauf have told me normal insulation is not suitable for rafters however I would have thought the counter battening on the underside will be enough to support any insulation above it? I understand why it might be needed on a roof where it is resting on the plasterboard but it shouldn't be needed here - am I correct?

I think I'm going insane trying to understand how to layer up my refurbished vaulted ceiling. The issue I guess is I am trading off between these 3 things: Acoustic performance (I have a train line at the back of the garden in a city) Thermal performance (I will be using a heat pump so want to get the U value down below 0.18) Ceiling height (Roof pitch is around 30 degrees and ive already lost some overhead height with wet underfloor heating) I'm currently thinking along these lines (from outside to in): 1. Roof tile 2. 25 mm Battens 3. Breathable membrane draped 10mm 4. 15mm air gap in 175mm rafters at 400mm centres 5. 150mm rockwool slab insulation between rafters 6. Tecsound 10 mass loaded vinyl 5mm 7. Vapour barrier 8. 50mm PIR in an unbroken layer 9. 50mm battens, space between filled with 50mm rockwool slabs 10. 17mm resilient bars to create service layer, non ventilated air gap, and decoupled ceiling 11. 2 layers of acoustic plasterboard (25mm total) 12. Skim coat That should give me a build up of 150mm and allow for recessed ceiling lights that won't interfere with the PIR layer. The tecsound further back will also counter act noise leaking through the ceiling lights I hope. But All the U value calculators I have found are very limited, even within the manufacturers range of options. And I can't begin to calculate the acoustic performance. It feels like I'm throwing grass into the wind and hoping for the best. I spoke to a couple of architects who seem to have their preferred methods (usually double plasterboard and as much PIR as can fit). Does anyone know a better way to do this ? Thanks

I think I'm going insane trying to understand how to layer up my refurbished vaulted ceiling. The issue I guess is I am trading off between these 3 things: Acoustic performance (I have a train line at the back of the garden in a city) Thermal performance (I will be using a heat pump so want to get the U value down below 0.18) Ceiling height (Roof pitch is around 30 degrees and ive already lost some overhead height with wet underfloor heating) I'm currently thinking along these lines (from outside to in): 1. Roof tile 2. 25 mm Battens 3. Breathable membrane draped 10mm 4. 15mm air gap in 175mm rafters at 400mm centres 5. 150mm rockwool slab insulation between rafters 6. Tecsound 10 mass loaded vinyl 5mm 7. Vapour barrier 8. 50mm PIR in an unbroken layer 9. 50mm battens, space between filled with 50mm rockwool slabs 10. 17mm resilient bars to create service layer, non ventilated air gap, and decoupled ceiling 11. 2 layers of acoustic plasterboard (25mm total) 12. Skim coat That should give me a build up of 150mm and allow for recessed ceiling lights that won't interfere with the PIR layer. The tecsound further back will also counter act noise leaking through the ceiling lights I hope. But All the U value calculators I have found are very limited, even within the manufacturers range of options. And I can't begin to calculate the acoustic performance. It feels like I'm throwing grass into the wind and hoping for the best. I spoke to a couple of architects who seem to have their preferred methods (usually double plasterboard and as much PIR as can fit). Does anyone know a better way to do this ? Thanks