Insulation for internal stud walls and above ceilings??

[IanR]

What have people used or plan to use for (acoustic) insulation of stud work walls and above ceilings.

 

Building Regs calls for minimum 40 Rw dB Airborne sound reduction.

 

What's the most cost effective product, that's easy to install to achieve this minimum or to preferably exceed the requirement.

 

I've just noticed the Architect that pulled together my Building Regs has specified Warmcel 500, which seems a little OTT and extra work to install.

 

Thanks.

[Oz07]

Rs45? Look for robust details or a general spec online

[Mikey_1980]

we used earthwool acoustic roll, works really well you can't hear a thing, or thats what I say when someone shouts for a cup of tea.

[IanR]

Something like this?

http://www.knaufinsulation.co.uk/products/glass-mineral-wool-rolls/acoustic-rolls/earthwool-acoustic-roll

 

What thickness did you go with?

 

I looked at this, but thought the 10Kg/m3 "felt" a bit lightweight when compared to other thermal insulation products like the RS45. But the proof of the pudding... so if it's worked for you! 

[ADLIan]

Building Regs require 'mineral wool' (this is glass or stone wool) min 10 kg/m3, 25mm (min) in partitions and 100mm (min) in intermediate floors. Density in walls is normally higher to give product mechanical strength for vertical use. Do not go too dense (more than approx 25-30 kg/m3?) as it's a waste of money. Warmcell is not included as generic BR solution so you would need indepependent test data for use in wall and floor of the same construction.

[Mikey_1980]

We used 100mm acoustic earth wool with 15mm  plasterboard and a skim finish as our finished walls

[TerryE]

Earthwool is a PITA.  It is so uncivilised handling it.  We used Rockwool Flexislab 50mm x 1200 x 400mm batts in both our stud partitions and in our intermediate floors.  Still not good to handle but a lot better than earthwool and its a lot easier to cut and is self supporting.  This is less than current BRegs for the ceiling insulation, but to be honest our BInsp didn't seem to be worried about it anyway.  The pre boarding out photos don't show any obvious difference between 50mm and 100mm.

[IanR]

In looking into the Rockwool Flexislab, I tripped over Rockwool's RWA45 Acoustic Insulation Slab. It's not got the "Flexi" edge, but is less than half the price based on TP's pricing.

 

Might get a couple of packs in to see if it's easy to install.

 

Thanks all.

[Oz07]

Sorry I think thats the one i used last rock wool RWA45. Seemed pretty stiff and self supporting. 

 

With regards to ceiling acoustic insulation I am pretty sure posi joists conform to english acoustic regs but not scottish regs (on their own). Although if the house was for myself i'd prefer a bit of ceiling wool aswell. 50mm would work well being the approx thickness of either I beam or Posi joist top/bottom rails.

[ADLIan]

Scot Regs pretty much reflect English Regs. 100mm mineral wool between joists.

[Oz07]

40db sound reduction was my understanding

 

http://www.mitek.co.uk/Products/Posi-Joist/Product-Brochure/

 

Note how much difference the 100mm wool makes! Less than 5%

Edited September 6, 2016 by Oz07

[Trw144]

Just reading that about posi joists and reference fire regs, am I reading correctly in that I don't need fire hoods over my down lights given I have 250mm posi joist, above which I have 22mm osb, 25mm insulation, 22mm chipboard and then final floor coverings?

 

i was going to lay 100mm insulation between posi joists for sound insulation anyway.

Edited September 6, 2016 by Trw144

[James13]

Did you put the 100mm stuff between in a 89mm timber stud wall (as in does it compact/squash) to go between the studs and plaster board or am I to get a smaller thickness?

 

 

[James13]

And where did you chaps get it from? 

[Trw144]

Insulation 4 less I used - I ll check on what price I got and let you know

[IanR]

19 hours ago, James13 said:

Did you put the 100mm stuff between in a 89mm timber stud wall (as in does it compact/squash) to go between the studs and plaster board or am I to get a smaller thickness?

 

 

 

I'm putting 100mm into 95mm studs following the advice from Rockwool that it will easily compress down. I assume though that performance will drop of if it's compressed too much. 

 

I got good prices locally from Collier & Catchpole BM

 

But the cheaper RWA45 Acoustic insulation is not available in as many sizes as the FlexiSlab. I've therefore gone with a mixture of RWA45 and FlexiSlab

 

The problem for me was RWA45 doesn't come in 400mm wide and cutting down 600mm was higher cost than buying 400mm FlexiSlab.

[Rob99]

As part of our internal alterations we will be replacing all of the ceilings downstairs. We've never had a particular noise problem (except from the loo in the ensuite above the living room!!) and wondered whether it is worth putting in any sound insulation and, if so, what type and thickness works well. 

 

Similarly we will have a ground floor room which may occasionally be used as a guest bedroom and which is next to the utility room. What would you recommend as a stud wall construction and insulation to provide some element of sound-proofing when the washing machine and tumble dryer are in use.

 

Thanks

 

[Onoff]

8 minutes ago, Rob99 said:

As part of our internal alterations we will be replacing all of the ceilings downstairs. We've never had a particular noise problem (except from the loo in the ensuite above the living room!!) and wondered whether it is worth putting in any sound insulation and, if so, what type and thickness works well. 

 

Similarly we will have a ground floor room which may occasionally be used as a guest bedroom and which is next to the utility room. What would you recommend as a stud wall construction and insulation to provide some element of sound-proofing when the washing machine and tumble dryer are in use.

 

Thanks

 

 

Gyproc Soundbloc at a guess. I know Rockwool batts are better at soaking up sound than pir. 

[Moonshine]

11 hours ago, Rob99 said:

As part of our internal alterations we will be replacing all of the ceilings downstairs. We've never had a particular noise problem (except from the loo in the ensuite above the living room!!) and wondered whether it is worth putting in any sound insulation and, if so, what type and thickness works well. 

 

Similarly we will have a ground floor room which may occasionally be used as a guest bedroom and which is next to the utility room. What would you recommend as a stud wall construction and insulation to provide some element of sound-proofing when the washing machine and tumble dryer are in use.

 

What is the existing floor build up? How much space have you got free for the stud wall as this will have an impact on the degree of sound insulation you can achieve.

[Rob99]

It's an internal garage conversion so floor is curently concrete slab. New floor on top will be 100mm slab insulation, 70mm reinforced screed, 20mm overlay UFH system and 15mm engineered wood finish. The stud wall isn't up yet so can be flexible on size.

[Moonshine]

I am thinking of what the existing floor build up is where you are taking the ceiling down (between ground and first floor), the ground floor construction is fairly unimportant acoustically.

 

As for the stud, presuming that you are going for timber i would suggest two layers of 12.5mm soundbloc either side of the stud, with 25mm insulation (APR1200) in the cavity this gives you Rw 46 dB (above min requirement of Rw 40 dB). Bump the cavity insulation thickness and density up a bit will give likely give you 1-2 dB increase in performance. But if you want to go over this, adding a resilient bar to one side and having 50mm of insulation will give you Rw 56 dB (also have a look at the white book for suggested detailing p243).

 

https://www.gyproc.ie/sites/default/files/A046005.pdf

 

This would likely deal with the airborne sound pretty well, but as its a lightweight partition it won't be as good as a masonry wall for low frequency noise. 

 

As its a washing machine and tumble dryer, make sure that these are not touching / connected to walls as to allow structure borne noise, and maybe even a resilient mat on the floor to decouple it from the floor slab if its a shared slab to the room next door.

[Rob99]

Just getting back to this as not been online for a couple of weeks..........

 

Stud wall is 90mm so can put a couple of layers of soundbloc on and insulation in cavity so all should be good. To be honest the w/m and t/d wont be used at night anyway.

 

Intermediate floor construction is 185x50 joists with 22mm chipboard flooring above, so thinking that RWA45 would be a good option.

 

Now wondering about what thickness. Is there much real acoustic difference between 75 and 100 thickness as with cables, ceiling spots etc the  100mm might be too thick anyway?

 

Cheers

[CC45]

I phoned rockwool and was told to use 50mm in a 90mm stud wall - airgap both sides was important.  Add on soundbloc if want more soundproofing.

[Gav_P]

I used the rockwood RWA45 and jammed it every possible space in ceiling and walls. Seems to have worked very well as we used to be able to have conversations between floors/ rooms but now have to shout to be heard.

 

The key for making it work is to make sure you seal round the edge gaps... noise can sneak through the smallest of holes, and will annoy the s**t out of you if you can still hear things after all the effort and expense of the rockwool.

 

i also used the rubber insultation strips between joists and chipboard flooring... not sure if it did anything, but it’s cheap so worth trying. And having a young child and big dog running about I wanted to reduce the floor pounding noise!

[Rob99]

What thickness of RWA45 did you use @Gav_P ?