Sound test

[emphasis303]

Hello Everyone

I currently have 6x2 joists at 400 centres on the 1st floor.

If I insulate between them using an acoustic roll such as isover apr 1200.

Then overlay with existing floor boards then lay 18mm T&G chipboard, then lay laminate flooring with the correct underlay, from your professional or non professional experiences do you think I will pass a sound test in compliance with Part E?

The underside of the joists will have 12.5mm plasterboard and a skim of plaster.

Many Thanks[/code]

 

[emphasis303]

Sorry should have said, this is for an existing renovation of a 3 storey late Victorian mid terraced property.

 

[jeds]

Will this floor be a separating floor (between flats) or a floor within a single dwelling?

 

[emphasis303]

Yes it will be

Thanks

 

[freddiemercurystwin]

So a separating floor between 2 flats or a floor within a single dwelling?

 

[emphasis303]

A separating floor between two flats.

Apologies for not making this clear, I posted a bit too early in the morning.

Cheers

 

[jeds]

In that case, no. It won't pass a test. You will need an acoustic rated floor layer and probably an additional ceiling layer as well with resilient bars. And then there will be some risk due to unknown properties of the existing layers. That lot might overload your joists as well so needs to be checked properly.

 

[emphasis303]

Sorry double post

 

[emphasis303]

Thanks for your reply

Since posting I have been reading product data sheets and isover claim that 100mm of their insulation with 18mm t&g chipboard and a single 12.5mm layer of gyproc wallboard 10 plasterboard in 8x2 joists will achieve the 40db sound insulation requirements in a single dwelling.

It states for party floors the requirement is 45db for airborne sounds.

If I placed a 25mm layer of something like rock floor would that be suitable?

Thanks

 

[jeds]

It doesn't work like that. Sound measurment is extremely complicated but in simple terms the db scale is not linear - it is logarithmic. 3 dbs are not one third of 9 dbs. To get from 40db sound reduction to 45 is very significant. I've outlined the sort of spec that might do the job above. But as I said, when you make up a non standard system (i.e. one that has not been tested) you are always taking a risk.

 

[emphasis303]

Thank you very much for your replies

So what I propose is to insulate using 100mm acoustic roll between the rafters, then for the underside of the ceiling install metal resilient bars to the joists, then install 2 layers of 12.5mm plasterboard.

The top of the joists will have

Original floorboards 16-18mm
Resilient layer of Rockfloor 25mm
18mm chipboard
Fibreboard laminate underlay 6mm
Laminate flooring finish.

From your experience would you say this would be sufficient to meet the regs?

Thank you

 

[TicklyT]

As above, every 3dB of attenuation is equivalent to halving the amount of noise, so getting from 45dB to 40dB means achieving something approaching a fourfold reduction in noise transmission.

 

[emphasis303]

Thanks for your reply

I understand that to even achieve a 3db reduction is difficult.

Do you see any issues in my proposal?

Thank you

 

[freddiemercurystwin]

A test for sound either works or it doesn't and nobody on here will be able to tell you if it will pass or not.

When it comes to choosing a specification to be used in a separating floor generally you choose one of the standard systems comprising of the various different materials that has already been tried and tested from Building Control or from the various manufacturers out there who have published their tested systems/specification. Deviate from these standard systems and you're on your own.

Is this actually going to be tested anyway?