Soundproofing 95mm bathroom stud wall

[oranjeboom]

Looking to soundproof the wetroom/shower as much as possible. My daughter's taste in music....hurts everyone's ears so my son whose bedroom is on the other side of the stud wall won't want to hear her 'sing' in the shower! It's a 95mm stud wall with Schluter kerdiboard and 9mm tiles. My plan was to either fill the stud wall with PIR (95mm) or use up my acoustic loft roll type stuff (Superglass roll) that I still have lying around. Alternatively, I was going to go fit the acoustic stuff in the studs and then add a 50mm PIR sheet up the wall, ending up with 145mm wall (plus PB). 

 

What's best?

 

 

[Russell griffiths]

If your not bothered about the extra width then do it properly and use an isolation stud against the existing studwork, I can’t for the life of me remember what it is called, but it works by having a gap between the two studs

sound transfer is best avoided by having the two areas of whatever material not touching each other, so a void between the two walls is best. 

 

It could be called a resiliant bar. ????

[ADLIan]

PUR/PIR has no acoustic properties so do not use this. Fully fill the studs with glass wool (check with manufacturer that its the right type). To improve things further add 2 or more layers of plasterboard each side to add mass to the wall or consider use of resilient bars to decouple the plasterboard from the studs.

[Russell griffiths]

like that

[Moonshine]

Fill the the 95mm stud cavity with 100mm mineral wool (or similar porous insulation) min density 24 kg/m3 (loft is usually around about 12 kg/m3). DO NOT USE PIR!

 

You are going to want to de-couple the wall linings from the stud work, with a resilient bar or equivalent.

 

Next you want to provide some mass to the construction, so on the resilient bars fix two layers of 15mm dense plasterboard (e.g. SoundBloc) on the bedrooms side, on the bathroom side, you can use a cement based board such as 12mm hardie backer. If you are going to tile the whole wall you can just have one layer this board, as the tiles will give the additional mass needed.

 

if you could make it 145mm thickness, you could go for a staggered stud wall construction. 

 

Also if you can don't put any electrical sockets or penetrations in the wall linings.

 

If you do end up using resilient bars make sure you use two different lengths of screws, a potential on site issue if too long a screw gets used on the inner layer of plasterboard, they go right through the resilient bar and potentially into the stud, making the bar pointless.

 

Edited April 5, 2019 by Moonshine

[nod]

56 minutes ago, oranjeboom said:

Looking to soundproof the wetroom/shower as much as possible. My daughter's taste in music....hurts everyone's ears so my son whose bedroom is on the other side of the stud wall won't want to hear her 'sing' in the shower! It's a 95mm stud wall with Schluter kerdiboard and 9mm tiles. My plan was to either fill the stud wall with PIR (95mm) or use up my acoustic loft roll type stuff (Superglass roll) that I still have lying around. Alternatively, I was going to go fit the acoustic stuff in the studs and then add a 50mm PIR sheet up the wall, ending up with 145mm wall (plus PB). 

 

What's best?

 

 

I do this for a living 

Often we use 25 mil acoustic 

insulation 

There’s a misconception that you need to pack the wall up with insulation 

Standard party wall between two student blocks is two 50 mil studs 120 void One layer of acoustic insulation To stop any sound bouncing around 

Studs done in MF 600 centres Braced at 1200

one layer of 15 mil soundblock on each 

Ive two bathrooms back to back and you can’t hear someone shouting on the other side of the wall 

[Moonshine]

51 minutes ago, nod said:

Often we use 25 mil acoustic insulation 

There’s a misconception that you need to pack the wall up with insulation.

 

British Gypium usually spec wall systems with 25-50mm APR1200, which is 12kg/m3, and true you don't need to fill the cavity.

 

But.... by going denser and thicker with the insulation you will get a better overall result (as long as its not overly compressed), especially at low frequencies.

 

On a limited area of wall the marginal extra cost is probably worth it if the overall aim is acoustic seperation.

[oranjeboom]

2 hours ago, nod said:

two 50 mil studs 120 void One layer of acoustic insulation

Thank nod, so as i understand:

 

50mm stud---/---120mm void--/--50mm stud (with the void containing one layer of acoustic insul)?

 

***just seen the other responses after posting this, so will digest***

 

Yes, resilient bars I have come across. Thanks all.

Edited April 5, 2019 by oranjeboom

[joe90]

I came across a site (somewhere) where a stud wall was built with verticals staggered but overlapping so apart from foot and header plate (4x2) the 3x2 verts were not touching each other and acoustic foam weaved itself between them. (Needs a diagram really ?).

[Moonshine]

38 minutes ago, joe90 said:

I came across a site (somewhere) where a stud wall was built with verticals staggered but overlapping so apart from foot and header plate (4x2) the 3x2 verts were not touching each other and acoustic foam weaved itself between them. (Needs a diagram really ?).

 

That's a staggered stud, Google images will come up with loads.

[CC45]

worth speaking to tech depts - rockwool was v helpful when I asked.  Advice for a 90mm stud wall was 50mm of  RWA45 - not touching either side wall & then soundbloc board or 15mm normal PB.  More layers of PB if necessary.

[ragg987]

All good stuff above, but do remember there are three modes of sound transmission and you need to tackle them all equally.

 

AIR-TO-AIR TRANSMISSION - e.g. through holes and other apertures. This is usually the floor or ceiling junctions - seal these carefully. Also, think about the doors (usually the weakest point) and if you have MVHR and were counting on gaps under the doors you will have to think again. This one is a lot more effort to solve, requiring baffles in the air-flow.

 

VIBRATION - e.g. vibrating drywall. As you mention "daughter singing" this may be less of an issue, vibration becomes more of a problem at lower frequencies. Staggered stud and resilient bar solves this problem.

 

TRANSMISSION THROUGH SOLID MATERIALS - which you can solve with the techniques mentioned above - mass (double plasterboard) and rockwool - no more than 65% of the void.

 

If you decide to go with double-plasterboard, suggest you consider a flexible "glue" (I used Green Glue - probably have some left lying around if interested) between the sandwich and pay attention to sealing all the way round on both layers, plus stagger and seal all joints. Done right this technique will tackle all three modes, above, to some degree.

[epsilonGreedy]

6 hours ago, nod said:

Ive two bathrooms back to back and you can’t hear someone shouting on the other side of the wall 

 

 

Is the spec of the dividing wall as per your student party wall?

[nod]

I’d did it pretty much for sound as the bathroom on our guest bathroom backs onto ours 

 

When we build party walls student acom or other commercial 

I build  them pretty much like I’ve said Only I add fire stops and a deflection floor and ceiling head 

These are built before any other walls or ceilings 

It’s all aboutmaking sure an even cavity is maintained 

Always in MF

Timber is a waste of time when it comes to soundproofing 

[Moonshine]

9 hours ago, nod said:

When we build party walls student acom or other commercial 

I build  them pretty much like I’ve said.

 

Always in MF Timber is a waste of time when it comes to soundproofing 

 

Have you ever had one of those wall constructionas sound tested? Based on your described construction of one layer of 15mm SoundBloc on independent 50mm metal studs and 25mm insulation, I would say that is very close to the min requirements of approved document E for student halls.

 

In relation to acoustics, timber Vs metal stud the difference negligible, and timber is not a waste of time. Timber/metal Vs masonry, that's a different story

[nod]

All are sound tested 

 

part walls are normall two layers of soundblock First layer is a horizontal 600 mil strip on the Bottom and the next stood vertically 

next board is stood virtually staggering all joints The other side is done the same 

It’s the junctions were you are most likely to get sound transfer 

On T F we tend to use horizontal planks and lots of insulation 

You can on play the cards that you are dealt 

[Moonshine]

On 06/04/2019 at 08:59, nod said:

All are sound tested 

 

part walls are normall two layers of soundblock

 

Ah, that makes sense, as above you were stating that this was a single layer of SoundBloc.

 

What you have describe sounds like this https://www.british-gypsum.com/white-book-system-selector/find-by-system-reference?systemRef=A216001&tab0=1

 

IMO It is still pretty damn close to just exceeding the requirements of ADE.

 

Are you able to share the results of the sound tests of how its performing in the field?

 

 

Edited April 8, 2019 by Moonshine