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Acoustic plasterboard ?

Discussion in 'Plastering and Rendering' started by wwwebber, 26 Nov 2018.

  1. wwwebber

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    Hi, some advice would be appreciated here.

    We are looking at overboarding the upstairs ceilings. Now, as the loft rooms are in use we also want to reduce sound transmission between the upstairs rooms and the loft rooms.

    My question is - is it worth spending a little extra to use acoustic plasterboard for the overboarding ? and if so is it then worth using two board layers ?.

    We are already looking at putting rockwool between the floor joists in the loft.

    Just got one chance to get this right so would appreciate opinion.

    Thank you.
     
  2. bobasd

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    are you sayin that youve got the flooring in the loft already lifted or do you mean you intend to work from below after removin the ceilings?
     
  3. SFK

    SFK

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    Webber
    Acoustic insulation is always a nightmare subject as it is subjective, and (for example) after spending a fortune on a ceiling the sound might then go through the joists, or etc etc. So any methods below are simply to reduce the sound.

    But I feel that filling the gap with loose insulation of some sort is always good at making the wall sound more solid and stopping a some noise. Normally I just use left-over rock wool or loft insulation, and as it is compressible (and being used for Acoustic insulation) then it matters less if it is 100mm thick and squashed to the 89mm inside the ceiling.

    I have never used it, but I see wickes has "Earthwool Acoustic Roll 50mm 15.6m2" that seems suitable for your application to stop a bit of noise:
    https://www.wickes.co.uk/Earthwool-Acoustic-Roll-50mm-15-6m2/p/143388
    or there is normal loft insulation that is cheaper.
    https://www.wickes.co.uk/Knauf-100mm-Space-Loft-Roll-Bottom-Layer-Roll---8-3m2/p/166877
    and then there is this (which I have used once), but is expensive:
    https://www.wickes.co.uk/Wickes-30mm-Acoustic-Insulation-Slab-3-6m2-Pack-5/p/161189

    Regarding Soundboards, yes they do make some difference because they are heavy and absorb some of the sound.
    But they are very very heavy so make sure that ceiling joists will take the weight (was loft properly converted with properly rated joists?), and ensure you are strong enough to be able to lift them to fit them.
    As you already have one ceiling (you are over boarding) I would be tempted to stop at one layer.

    Underlay and carpet in both rooms also makes a massive difference (the more you can stop the sound from being formed the better).

    sfk
     
    Last edited: 27 Nov 2018
  4. wwwebber

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    Hi, not lifted floor yet but will be doing next year. I am not removing any ceiling - simply overboarding.
     
  5. wwwebber

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    @SFK

    Yep just trying to do the best I can - I realise that I will not eliminate all noise but as I say - only got one chance to get this right :)

    For the soundboards, the loft floor does need re-enforcing as it's currently only 3x2 and that is planned for next year too with extra joists. I do take your point though - stay at one layer of soundboard on the ceiling due to weight etc.

    Thanks very much for the links - I will check them out. I've been looking at the Rockwool website and I simply cannot fathom which is the best for me.

    Cheers.
     
  6. SFK

    SFK

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    Webber,
    You are correct, with soundproof you can only every do the best you can with the budget you have. Noise will always get past and you will always wish you spent more (or less as it gets very expensive).

    BUT I am not sure I am happy with you putting Sound boards that weigh 30kg each and heavy acoustic insulation slabs onto 3x2 joists. That is a lot of weight onto small joists.
    https://www.wickes.co.uk/Knauf-Sound-Panel-Tapered-Edge---12-5mm-x-1-2m-x-2-4m/p/224657

    Plus, if you are having the loft done in the future, building control are going to be asking for Fire Boards and/or Fire rated rockwool.

    SFK
     
  7. wwwebber

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    @SFK

    Yeah I get it. Maybe I should wait until I have sistered the floor joists before having the ceilings downstairs done - if at all.

    To be clear the loft rooms are already "done" ie already official rooms with some insulation + dormers windows etc. The house is a 1820s property and they have always historically been rooms (servants quarters apparently). I am not going to get BC involved as I don't believe it will ever meet modern standards (room height, floor joists, insulation thickness etc) so what I am doing is upgrading where I can - all will be improvements. Thanks for the advice.
     
  8. SFK

    SFK

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    Webber
    Noted. And as they are original loft rooms they do not need to be upgraded to modern standards UNLESS you make other large structural changes.

    Perhaps try the Acoustic Rolls and/or slabs (using both makes for two different densities that improves sound absorption) between the joists first then. That will be a cheaper and less messy option that can be reused if you do do the loft.
    You also won't break your back trying to lift and screw 30kg panels to the ceiling and then re-plastering mess.

    SFK
     
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  9. wwwebber

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    @SFK

    You seem to know your onions - what do you think about this question I have (unanswered from another thread).

    Regarding insulating my roof :-

    I don't have any membrane at all or any insulation between and the tiles are open tiles (ie plenty of air gaps for ventilation). So I am going to remove the existing 50mm insulation backed plasterboard that is below the rafters. My rafters are only 75mm deep so I am going to put 50mm PIR in - leaving a 25mm gap, seal with foil tape and replace the existing 50mm insulated plasterboard. I'm not seeking BC approval - I just need to improve things. Please shout up any issues you may see here.

    Cheers.
     
  10. SFK

    SFK

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    Webber,
    "You seem to know your onions", nope, I am only a DIYer. So the issue is that I do it only once, and then know how i should have done better next time, but rarely get to do it again.
    Regarding your loft, from what others have said what you are suggesting is very common in lofts. And the fact that you are keeping airflow between PIR and tiles is good.
    And for future you can always have tiles removed, breathable mebrain put in and tiles put back on.

    PIR again has diminishing returns. Increasing from 50mm of PIR to 100mm of PIR will not halve your thermal losses - but it will improve it. The key is in the detailing, the new PIR must be sitting snugly against the old PIR (no point having a 1inch gap (which I have seen) and the cold air then simply moves around the PIR). Some use Spray foam (in moderation) to stick the edges of the sheets together and fill any gaps between the sheets and Joists.

    Nice details here, BUT AS THEY SAY NEVER EVER EVER allow anyone to use spray foam insulation on your tiles, it causes damage and devalues your house:
    https://www.diynot.com/diy/threads/loft-insulation-is-it-worth-it.150976/#post-1018926

    SFK
     
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  11. Christopher83

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    First ever post, here goes. Our neighbours have kids the same age as our kids, but we put ours to bed at 7pm and they put theirs to bed at 11pm. Their dining room/kitchen is all open plan, and they have laminate flooring. The noise is coming through our dining room, our living room and my son’s bedroom.

    Last week paid plasterers to work on those walls with acoustic foam & double plasterboard, but the noise (foot fall, shouting, screaming) is still really bad.
    Do I bite the bullet and try to find the money to pay for the all singing all dancing sound proofing specialists, or try stuffing wardrobes with clothes & bookcases with books and push them all against the adjoining wall?

    Or a different approach altogether? Sorry for essay-length message. We are at our wits’ end.

    Thanks
     
  12. wwwebber

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    Hi, I would certainly suggest that you need to something more than double boarding but I'm no specialist. I would suggest that you create a brand new thread in here with the same text and you should get some constructive replies.
     
  13. Christopher83

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    Many thanks mate, I will do that now. I appreciate the reply. Cheers, Chris
     
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