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Ceiling Acoustic insulation solutions, Iso-Max, GenieClip etc.

Discussion in 'Building' started by pls1, 21 Jan 2019.

  1. pls1

    pls1

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    There are are a number of solutions on the market I've been researching for soundproofing a ceiling due to noise from neighbouring flats above (both airborne & impact noise).

    In my case, it's a Victorian property divided into flats. Joists are deep (8x2) and existing lath & plaster ceiling removed. Floor above is timber floorboards and some cr*p carpet (no underlay) or equally cr*p vinyl effect laminate stuck to 9mm ply over floorboards. These are separate flats so no chance of insulating from above unfortunately. No possibility to drop ceiling much due to window height either.

    Current plan is 100mm Rockwool RW3 between the joists (for airborne noise) and one of the following for impact noise:

    Oscar ISO Mount
    Expensive & more difficult to install than the rest but best for minimal ceiling loss height & uses standard GL1 metal channel.
    https://www.oscar-acoustics.co.uk/acoustic-solutions/oscar-iso-mount.asp

    Genie Clip
    Similar to ISO Mount in design but even more expensive & uses proprietary furring channel
    https://www.ikoustic.co.uk/systems/genieclip®-lb2-single

    ISOMax Clips
    Rubber mount for proprietary metal channel that screws to bottom of joists. Cheaper than solutions above but more loss of ceiling height.
    https://www.soundproofingstore.co.uk/store/Isomax-Clip-System-For-Ceilings-p52900686

    Resilient Bar
    Widely available and cheaper than the rest but potentially worse acoustic performance & would require 2 layers of 12.5mm Soundbloc plasterboard to achieve a decent result.

    There are also various rubber membranes available which stick between layers of plasterboard but no real idea if these work or not.

    Anyone any feedback on using any of the above systems and what the results are like?
     
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  3. 23vc

    23vc

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    I’ve done 100mm rockwool between joists, resilient bars and single 12.5mm plasterboard. I’d certainly say the result was noticeably better than just a bit of rockwool in the ceiling. Difficult to quantify a “decent result”.

    As an approximation, I’d say it reduced the noise level (from above) from hearing pretty much every movement and word, to hearing occasional faint floorboard creaks and raised voices.
     
    Last edited: 22 Jan 2019
  4. Yannis.sp

    Yannis.sp

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  5. Michaelsf90

    Michaelsf90

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    What rockwool did you use? I'm in the process of doing a wall myself. I've been told and adviced that 2 inch of acoustic slabs at 48kgm3 is the best. Anything over that won't make much difference for the cost. I was thinking of using rwa45 50mm for the walls and flanking noise in the ceiling and floor. I'm overboarding my ceiling downstairs but it doesn't need to be soundproof. But to make it slightly soundproof I was thinking 25mm rwa45, resilient bar and one layer of soundbloc board. Plus the lathe and plaster ceiling will still be up and intact.

    As for the OP from my research the genie clips seem to be the best and seem to be guaranteed but are very expensive. Id chance with the resilient bar for the cost and space aspect. Just make sure you pay attention to detail. Install correctly. Don't short circuit. Make sure the plasterboard has a 2-5mm gap around the edges and seal with acoustic sealant. Seal the joints as well
     
  6. JohnD

    JohnD

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    If it's sound, I've found a thick lime L&P ceiling is very good for blocking noise, no doubt due to its mass.

    Look for any holes or gaps, usually around pipes but may also be for wiring, especially around ceiling roses. Wiring is pretty certain to have been done long after the house was built.

    If you are unlucky some buffoon will have cut great holes in it for downlighters.
     
  7. 23vc

    23vc

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    Rwa45 I think. Are you saying your option’s better (ie denser despite being half the thickness)? Be interested to know if it is.
     
  8. Michaelsf90

    Michaelsf90

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    Definitely use acoustic insulation slabs. My guess is the better the kgm3 the better it performs. But someone who builds music studios told me two inches at 48kgm3 will perform excellent. More than that is good but isn't really worth what you pay for. When it comes to sound air cavities and different densities are what disturb the sound waves and help take the energy away. So imagine you have your wooden floor above. Air gap. Rockwool. Resilient bar. Air gap. Plasterboard. All different densities. Double boarding helps but to double board it would be better to use 15mm soundbloc and then 12.5mm on top of that. Different densities. I'm definitely only using 25mm in the ceiling because of cost and 50mm in the walls. In the walls I'm going to use rw3 which is 60kgm3
     
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  9. Michaelsf90

    Michaelsf90

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    You are correct. Spotlights in the ceiling. Upstairs you can hear every word from downstairs. That's why I'm overboarding. I'm not too fussed about the sound from downstairs just if it's going to be boarded we may as well attempt to muffle some of the sound. It's more noise from the neighbours that winds us up so I'm investing more in the soundproofing the walls
     
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  11. pls1

    pls1

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    Thanks everyone, some interesting opinions.

    I'm not convinced by genie clips or their equivalent Oscar ISO mounts especially in terms of cost over say resi bars. I think they are certainly good at reducing the amount of ceiling height lost, but most of the noise reduction (airbourne & impact) seems to be down to the density and mass of the materials used.

    The building control officer who came round mentioned about flanking noise where some of the noise (especially impact) will come down the walls anyway regardless of the ceiling construction and efforts to soundproof it. Losing room space by soundproofing the walls as well unfortunately isn't an option.

    At the moment thought is to go with resi-bars but spend more on the plasterboard. Again there are various types and thicknesses I need to get my head around from the likes of Knauf, Gyproc etc.. :confused: Anyone with any experience of Soundbloc, DB board etc, I'm all ears !
     
    Last edited: 28 Jan 2019
  12. 23vc

    23vc

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    Personally I find it easier to go with 2 layers of normal boards, than the extra weight/fact that the sound bloc ones only come in 8x4s and I’m a 6x3 kinda guy. Not sure how it compares cost wise, or acoustic wise for that matter, but at least the joints are staggered so I’d imagine it’s fairly effective.
     
  13. Michaelsf90

    Michaelsf90

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    I'm going to be starting mine in the next few weeks so I will keep you posted. Flanking noise is an issue but just go how far you think you can go with the budget you have. I'm overboarding my ceiling anyway so il treat the ceiling and floor for flanking noise. The different densities is the logically way of thinking. I was thinking of putting in the acoustic underlay for laminate flooring between the plasterboards. It acts as a vapour barrier as well. I was wondering have any of you thought about moisture? The fact an air tight cavity with no ventilation is being created? But I'm also thinking of different densities. Soundbloc board 15mm, the acoustic underlay which is like 3mm polyethylene sheet then 12.5mm soundbloc board. At the end of the day creating a false wall with insulation and double board surely has to do something!
     
  14. Michaelsf90

    Michaelsf90

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    Soundbloc is twice as expensive. I've considered using soundbloc and fireline on top of that seeing as fireboard is also dense!
     
  15. Michaelsf90

    Michaelsf90

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  16. pls1

    pls1

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    A good link thanks. So it looks like Knauf Soundshield has the best density against thickness compared to Soundbloc, DB board etc. 1 layer of 15mm followed by 12.5mm on a ceiling would give a combined weight of 25 kg/m2 vs 23.2 kg/m2 for Soundbloc. Whether that difference is noticeable in reality remains to be seen! :cautious:
     
  17. StephenStephen

    StephenStephen

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    Indeed yes! We've lifted a floor to find a really good job of insulation, which has then had just that done to it. The 'downward pointing hot torch' arrangement will soon be replaced with LED strips, and insulation holes filled...
     
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