Soundproofing in new extension.

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peweuk

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I am building a new extension on my own on building notice.

It consists of adding a second storey to an existing single storey extension used as a lounge. The second storey will be for 3 bedrooms.

I am currently tiling the roof after Building control inspected and passed the roof construction.

On her last visit the BI told me she will next want to inspect when I have put in the joists for the upstairs floor to check the sound proofing.

I have looked at Part L, and also looked at information from various suppliers of sound proofing and it all looks very confusing - not to mention expensive.

Could anyone with experience of installing soundproofing to meet the regs suggest the most cost effective way of meeting the regs (as it is a domestic dwelling I am not overly concerned with the level of soundproofing - the existing cottage doesn't have any nor has any previous dwelling and its never caused us a problem). I just want to meet the regs with minimal cost.
 
Thanks Freddy - I meant part E :oops: I was looking at part L for something else.

So from a brief read of this (again) it seems that all I need is a min 100mm mineral wool between joists (and good carpet underlay upstairs for impact noise reduction). Or is that too simplistic?

For dividing stud walls on the first floor am I correct that 100mm of mineral wool in between the studs will also suffice (possibly twin plasterboard on the walls to further reduce noise).

Thanks again.
 
Well, for the floors you need to make sure that your plasterboard and decking achieves the standards (densities) required in section 5.23. You do not need to use carpet if you do not want to.

Regards the partitions then sections 5.17 or 5.18 apply (assuming they're timber partitions). You can use either of these 2, again though you need to make sure that your plasterboard and achieves the standards (densities) required. The method in section 5.18 with the insulation will probably work out cheaper. Again, you can use Crown Acoustic Roll.

British Gypsum make a plasterboard called 'wallboard ten' (or something like that) specifically to achieve the magic minimum 10kg/m2. There are othe types of plasterboard you could use though which may or may not work out cheaper, British Gypsum make so many!
 
Thanks again Freddy.

These documents can be a bit of heavy going to read and it's really helpful when someone points you to the relevant sections.

Thanks for the info on the plasterboard - thats also useful.
 
thats correct. 100m mineral wool roll between the joists min 10 kg/m3 density.
Stud walls only require a min of 25mm and 1 layer of plasterboard (min density 10kg/m3) either side to acheive min 40db rating, so as freddy says Gypsum do a wallboard 10, it has a blue back on it. if you dont want to mess around hanging mineral wool roll in the studs or fixing a rigid acoustic insulation around the studs opt for 2 layers of soundbloc plasterboard to both sides you get the same result just the soundbloc costs more but less labour.
 
It's dead simple. The regulation specifies minimum densities of components, which basically means you have to use 22mm chipboard (instead of 18mm) and you can't use standard plasterboard.

For the floor use; 22mm chipboard, 12.5mm Echeck or DBcheck plasterboard and infill with 100mm mineral wool with a minimum density of 10kg/m². You don't have to worry about impact sound.

For the partitions use; 75mm stud, (not 63mm) 12.5mm DBcheck or Echeck board and infill with 25mm mineral wool.

Having said that, I see hundreds of ceilings finished with 12.5mm standard board and have never seen it queried by an inspector.
 
It's different and more onerous if you are converting a house into flats as separate dwellings need a higher spec of acoustic attenuation between them.

Also needs a sound test to prove you got it right!
 
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