acoustic properties

[deuce22]

Hi.

Can somebody educate me on soundproofing. I have been told to use 100mm superglass acoustic insulation @ 10kgm3.
I have spoke with a soundproofing company about it and they have explained that, it is primarily based on density and it doesn’t matter what the material is.
So there were 2 things that I asked.

1. Would 2 standard 12.5mm plasterboards @ 23kg each give better acoustic properties than 1 acoustic board at 31.7 (as I can buy 2 standard boards for a similar price as 1 acoustic board).

2. If an insulation is not marketed as acoustic, but has a heavier weight per m3, than one advertised as acoustic, will this give better performance.

He said yes to both. I’d just like to check this because when speaking with Knauf, they didn’t understand what I was asking and couldn’t answer the question. Does anybody know if this is correct?

Thanks.

 

[ADLIan]

All of the standard mineral wool products, density range of say 10-50 kg/m3 will give the same acoustic performance once installed in a timber stud partition wall or intermediate floor. Performance is better with thicker insulation but tails of once above 75-100mm thickness. To improve the partition further it is down to adding mass with denser and/or multiple layers of plasterboard (or the use of resilient bars to decouple the plasterboard).

[deuce22]

  On 05/02/2025 at 10:24, ADLIan said:

All of the standard mineral wool products, density range of say 10-50 kg/m3 will give the same acoustic performance once installed in a timber stud partition wall or intermediate floor.

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So, a mineral wool that isn't advertised as acoustic, but is 15kg/m3, should be better than an acoustic insulation that is 10kg/m3?

Somebody has contacted me from Knauf and has said that it will have 0 acoustic properties.

I'll go with multiple boards then.

Thanks.

[JamesP]

From personal experience I have double boarded between bed and bathrooms and used resilient bars for the ceilings.

 

 

[SteamyTea]

  On 05/02/2025 at 10:14, deuce22 said:

it is primarily based on density and it doesn’t matter what the material is

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I don't think that is correct.  Shape and heat capacity are what actually does the absorption.  The shape allows for wave cancellation and the heat capacity is where the temperature rises because it has absorbed energy.

 

 

[Canski]

No technical info from me but … we used sound bloc plasterboard to each side and rock wool insulation between the studs and don’t hear anything through the walls except light switches