soundproofing ceiling

monkeyboy69

Active Member
Hi, I'm having lots of work done in the lounge, basically completely ripped out and the ceiling it about to be redone.
This is where all my kit sits and where loud m,usic or film volume can travel and I'm wondering the best method, albeit on a budget way of preventing sound from going upward to the bedrooms above.

ive found 2 products mineral wool and soundblocker quilt SoundBlocker Quilt

which could potentially be put between the joists.
I'm just unsure of whether this is the best method for sound reduction or whether im wasting my money this way and could perhaps employ a different method. Ive got several options available and wondered wheter anyone could help.

a) ceiling can be pull down, and either mineral wool or accoutic quilt can be added in between joists and ceiling retacked up and plastered
b) ceiling can be left and a secondary plastered board tacked over the top and reskimmed and then some sort of rubber matting can be layed under the carpet upstairs.

Just wondering how effective the mineral wool would be as it seems considerably cheaper than the quilt, or whether tacking another bit of plasterboard over the top would be as good or i go the whole hog from underneath and put the quilt in, or just make it easier for myself and stop it by approaching it from the bedroom floor aspect.

any tips guys
 

buzlightyear

Active Member
Fermacell

Im about to get this put into a home studio as the acoustic properties are meant to be good. Its a little more expensive than plasterboard but as you dont have to plaster it you will save a little money.
Ive not heard it in action so to speak but im assured its good stuff
 

Ted White

Novice Member
I might suggest if the plasterboard is gone, installing a medium density of mineral wool. Don't over compress.

Then if you can find redilient clips + channel there, use it to decouple the new plasterboard from the old wood joists. In a pinch, consider resilient bars.

Then double plasterboard for the mass.

This would be your least expensive high performance solution.

The solution isn't some interesting insulation, the least expensive works just as well. The quilts are not as absorptive as the insulation, and not as massive as plasterboard.
 

gfinlayson

Standard Member
When I refurbished my house, I decided to 'deaden' the ceiling as the room was highly reflective. I fitted resilient bar to the beams, fitted a 50mm layer of Rockwool RW3 above the resilient bar, then reboarded in 1/2" plasterboard. The difference was quite amazing. Much less sound reflection and no noise from footfalls upstairs. I got the RW3 very reasonably from my local Encon Insulation Depot. Gyproc resilient bar is quite pricey - I got some Speedline from FGF at about a third of the price.
 

dave_gt

Novice Member
My suggestion for the most effective (albeit not at all cheap) solution would be a suspended plasterboard ceiling.


If you want to make the sound insulation of the new ceiling as good as it can be within reason, use new independant joists fixed to walls with extra support from resilient hangers if desired in order to create a void of at least 5" / 125mm between your existing ceiling and the new suspended ceiling. A plasterboard ceiling hung using resilient bars would give a good benefit, but bars usually create a smaller void which renders the ceiling not as effective as with a bigger void. It depends how good you want your ceiling and how much you want to spend.


To reduce sound you need a lot of mass, and some separation between the layers of mass. The independant joists separate your new ceiling from the existing floor/ceiling structure. This separation is vital - if you just screwed two more layers of plasterboard to the existing ceiling it would be absolutely nowhere near as effective as a genuinely independant suspended ceiling.


The suspended ceiling itself should be constructed from two layers of plasterboard - ideally 12.5mm or 15mm and the two layers should be overlapped so that joint lines are not on top of each other. You may find that a blue coloured plasterboard is available (called Soundbloc). This is more expensive but more dense than conventional plasterboard and this can improve the sound insulation of a suspended ceiling. It depends how far you want to go.


If you are serious about improving the sound insulation between your lounge and the room upstairs I suggest looking at a document many developers use when building houses/flats so that they pass the sound tests that are now required - Part E of The Building Regulations 2003. It is designed to give advice on sound insulation between different dwellings, but that is kind of what you want I believe. Go here Planning Portal - Approved Document E and download it for free (also known as 'Approved Document E').


The method you want is 'Floor Treatment 1' for 'dwelling-houses and flats formed by material change of use.' I believe that it starts at page 60 off the top of my head. The document gives full details of how to fit a suspended ceiling which should be very good.


One thing to bear in mind is that it is very difficult to significantly reduce sound. Indeed, the term 'sound-proofing' is technically incorrect as it is impossible to stop sound without creating a vacuum around your lounge - not easy! The most difficult frequencies to attenuate are low frequencies which are very prevalent in home cinema, so do bear in mind that even with a good suspended ceiling, you may not get the isolation of sound that you are looking for.


Have a look at that document and see if it helps. Sound insulation is very easy to get wrong and I have seen many people spend a lot of money and not end up with the performance they were hoping for because the design is flawed. Diagrams best describe what to do, so you may find Approved Document E of use. There is also information in there about flanking transmisson.



With regards to your suggestions:


a) Adding an acoustic quilt or mineral wool in the cavity next to the joists will help a bit, but only a bit. I doubt you'd perceive the difference as night and day though. Mineral wool would absorb some of the sound in the cavity next to the joists (it stops sound reverberating in the cavity, which improves matters) but isn't very heavy so isn't very good at actual sound insulation. The quilt is heavier but usually not as absorptive as mineral wool.


b) Tacking a second board over the existing ceiling will help a little bit but nowhere near as much as I think you wanting. An acoustic underlay on the floor above (such as Acoustilay) will make the footsteps of people in the room above quieter in your lounge but will make very little difference to lounge sound reaching upstairs.


Hope that helps!
 
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Ted White

Novice Member
My suggestion for the most effective (albeit not at all cheap) solution would be a suspended plasterboard ceiling.

If you want to make the sound insulation of the new ceiling as good as it can be within reason, use new independant joists fixed to walls with extra support from resilient hangers if desired in order to create a void of at least 5" / 125mm between your existing ceiling and the new suspended ceiling.

There is real danger inserting a sealed air cavity next to another sealed air cavity. I'm not sure that 5" is sufficient. DO you have data on this?

A plasterboard ceiling hung using resilient bars would give some benefit, but bars usually create a smaller void which renders the ceiling not as effective.

Resilient bars attached directly to the existing ceiling plasterboard will makes things considerably worse across a very broad spectrum. There is significant lab data that clearly describes this, though the method you describe is all too common.

To reduce sound you need a lot of mass, and some separation between the layers of mass.

Ideally, only one big separation.
This issue of an air cavity on top of another comes up frequently enough that I'm digging through any available data. I'd love to find that a 3" cavity will be large enough to get someone out of trouble, but the acoustic community has been moving away from air cavities under 5", and frankly I'm not certain what a safe depth is.

Thanks
 
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dave_gt

Novice Member
Ted,


My suggestion of 5" minimum is what is recommended in Part E of The Building Regulations in the UK. Out of perhaps 2000 sound insulation tests I have performed, those developers who have stuck 100% to the Building Regs have always passed those tests comfortably.


With regards to resilient bars - I'm not really a fan of them. I have seen many examples of suspended plasterboard ceilings hung using resilient bars. Some have passed the aforementioned tests while a few have failed by a handful of decibels, for various reasons (but usually incorrect installation or the void being too small). They are easy to install incorrectly but I am aware that successful ceilings can be hung using resilient bars and they can represent a cheapish solution which doesn't sacrifice too much headroom. I am not one to rubbish another mans opinion and at least two posts had mentioned their use so I was happy to agree that it would 'give some benefit.' Sound insulation is so easy to cock up that my advice was and remains to follow a suggested method in Approved Document E if anyone is serious about improving sound insulation.



As to separations, yes, the bigger the separation the better but multiple separations can be used to great effect. The dividing walls between a lot of cinemas are multiple plasterboard jobs with several independant layers fixed to timber or metal stud frames. Sound 'hates' travelling through the plasterboard to air to plasterboard to air interfaces and so the more of those interfaces that are employed, the more attenuation can be gained. Massive attenuation has been achieved with just plasterboard and several frames set about 6" apart from each other. Conversley, an example of multiple separations I have witnessed that can be bad is if you already have a suspended plasterboard ceiling which has been added to an existing floor and you add another independant suspended plasterboard ceiling. The 'middle celiing' can be set into resonance which causes a reduction in performance. Only seen that once though.
 
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Ted White

Novice Member
Ted,

My suggestion of 5" minimum is what is recommended in Part E of The Building Regulations in the UK. Out of perhaps 2000 sound insulation tests I have performed, those developers who have stuck 100% to the Building Regs have always passed those tests comfortably.

But no studies that you are aware of regarding the 5"? That's my querry / concern. We get called in for very high isolation requirments that often contain significant low frequency waves. The 5" is a fine distance for beneath a solid slab ceiling, but I have yet to see data on the (larger) air cavity depth next to another air cavity. I would be quite grateful if you knew of such data.

With regards to resilient bars - I'm not really a fan of them.

I hate them personally, for all the reasons you mentioned. Resilient clips and channel are much better performing systems but I'm not sure these systems are readily available over there.


As to separations, yes, the bigger the separation the better but multiple separations can be used to great effect. The dividing walls between a lot of cinemas are multiple plasterboard jobs with several independant layers fixed to timber or metal stud frames. Sound 'hates' travelling through the plasterboard to air to plasterboard to air interfaces and so the more of those interfaces that are employed, the more attenuation can be gained.

I have to disagree. While many walls are specified to have interveening leaves as you describe, they are at the distinct loss of performance. These independant layers are there primarily for fire code.

Massive attenuation has been achieved with just plasterboard and several frames set about 6" apart from each other.
QUOTE]

More massive attenuation would be gained with a single large air cavity rather than several smaller. The single larger cavity will have a significantly lower resonance point, and therefore attenuate low frequencies much better.
 

dave_gt

Novice Member
Ted,


I'm afraid there are not any studies I am aware of relating to the 5" minimum void - I run a noise consultancy business and so while I am very involved with the practicalities of acoustics, I don't get involved much with research. However, the Association of Noise Consultants have regular meetings which we attend and as far as I am aware a 5" void being insuffiecient in this type of application has never been a topic which has been raised by any other consultants.


Please note that I am not referring to huge levels of sub-bass. Building Regs tests for houses are performed in the 100Hz-3150Hz range and perhaps surprisingly the nightclubs I have sorted out don't usually produce much sub bass. Generally, the "feel it in your chest" bass you get in nightclubs has a peak at 80Hz (indeed, occasionally problems have been sorted out by just cutting that frequency a bit. It seems that DJs find 80Hz quite appealing and I often find it is that frequency that is dominant across the bass). Most nightclubs don't generate massive levels of sub 40Hz bass. Some do, and of course good cinemas do, but I think I am teaching my granny to suck eggs when I say that getting a massive reduction in major sub-bass requires more mass, expense and space than most domestic households can bear.


Regarding multiple separations, we'll have to agree to disagree on that one :) When sound travels through a plasterboard to air interface it makes the transition from structure borne sound to airborne sound and vice versa. The more times that sound has to make that transition, the more attenuation will be achieved. Yes, there are always resonant frequencies to consider, both in the material used and the airgap between, but utilising different thicknesses of plasterboard and different widths of voids can assist in reducing the impact of resonant frequencies. Of course, the bigger the gap the better, but the improvement gained by having multiple spearations more than offsets the improvement gained by having one big gap, even if the resonant frequency of the air is lower in a large void.


Take an example - imagine we both had 4 pieces of 12.5mm plasterboard, 4 pieces of 15mm plasterboard, an unlmited number of independant metal stud frames for partitions and a 1000mm space in which we could put a wall. From your posts I think you would choose to bond 4 bits of plasterboard together and mount them on a frame, have a 890mm gap and then another 4 bits of plasterboard bonded together and mounted on another frame. That would indeed be a very very good wall. I would choose to have a 27.5mm plasterboard wall on a frame, 200mm airgap, 25mm wall on a frame, 500mm airgap, then a 30mm wall, 190mm airgap and then a final 27.5mm wall. In my opinion, experience and teaching the overall attenuation offered by 'my' wall would be better across the general frequency range. I am more than happy to accept your opinion, it is just that mine differs.



I'm not a regular poster on this forum and had happened upon this thread quite by accident. I was more than happy to give the original poster the benefit of my experience but had not intended on getting into a debate about sound insulation (interesting though it is, I unfortuantely lack the time to regularly debate things on the internet and by the time the evening comes around I've usually had more than my fill of acoustics)! So please do not be offended if I 'disappear' from the thread....


To the OP I would reiterate that if you want to really improve the sound insulation of your ceiling I recommend following a method detailed in the Building Regs, but please understand the limitations of separating floors, especialy at low frequencies. In the tests that I perform, a suspended double plasterboard ceiling implemented correctly usually achieves around 40 dB DnT at 100Hz - the lowest frequency we test at for Building Regs compiance. At frequencies under 100Hz, the attenuation will be progressively less. If you want to have a huge sub putting out high levels of genuine sub bass you will hear it in the room above irrespective of what ceiling you construct (within reason). Also do watch the flanking transmission.


All the best,


David
 
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Ted White

Novice Member
Hi David,

This is a very well researched phenomenon. If you're interested, I'd suggest you do a google search under "triple leaf" assemblies.

It's all about resonance.
 

Andrew Hudson

Standard Member
I have an old house and upstairs apartment has the most beautiful original hardwood floor which I don't want to cover up with carpets with staples. But it is too noisy for downstairs apartment when people walk around upstairs. I did place many area rugs, but still it is not working well.

What would be the best for this situation? My ideas are...

1. blow insulation into the space between upstairs and downstairs. about 8 inches high hollow space. I figured I can blow insulation from outside. least work and inexpensive. But this would do anything for soundproofing besides reducing the heating cost?

2. Insulation (soundproofing foams) and sheetrock for each bedroom downstairs. Most work and expensive. Is it worth doing this?

3. New thick area rugs for upstairs...this isn't cheap either!

Any advice? any idea? Please help...
 

Ted White

Novice Member
1. blow insulation into the space between upstairs and downstairs. about 8 inches high hollow space. I figured I can blow insulation from outside. least work and inexpensive. But this would do anything for soundproofing besides reducing the heating cost?
This isn't going to do much at all.

2. Insulation (soundproofing foams) and sheetrock for each bedroom downstairs. Most work and expensive. Is it worth doing this?
You won't want foam in between plasterboard. Better to add plasterboard with a quality damping compound.

3. New thick area rugs for upstairs...this isn't cheap either!

Any advice? any idea? Please help...
The best results would come from removing the existing plasterboard and addressing the vibration up in the joist cavity. That's where the vibration starts and this is much better if you arrest the vibration before it travels far.
 

ARNOLD AKIEN

Novice Member
I have an old house and upstairs apartment has the most beautiful original hardwood floor which I don't want to cover up with carpets with staples. But it is too noisy for downstairs apartment when people walk around upstairs. I did place many area rugs, but still it is not working well.

What would be the best for this situation? My ideas are...

1. blow insulation into the space between upstairs and downstairs. about 8 inches high hollow space. I figured I can blow insulation from outside. least work and inexpensive. But this would do anything for soundproofing besides reducing the heating cost?

2. Insulation (soundproofing foams) and sheetrock for each bedroom downstairs. Most work and expensive. Is it worth doing this?

3. New thick area rugs for upstairs...this isn't cheap either!

Any advice? any idea? Please help...
You don't really say an awful lot about the construction of that house of yours or of the nature of it's its conversion. You say .." I have an old house and upstairs apartment has the most beautiful original hardwood floor which I don't want to cover up with carpets with staples. But it is too noisy for downstairs apartment when people walk around upstairs. I did place many area rugs, but still it is not working well. "

The methodologies that you mention are unlikely to work in eliminating Noise. If you have control over the entire building and that building is a detached house then dropped ceilings and weight of the new ceilings plus some sort of acoustic stuffing betwixt the new ceiling and the old will help but you may still have flanking problems that will need to be addressed... and if its a terraced house ? Yet more problems that do call for expert advice and Loads of Money.


How old is the house? How has it been converted and to what? Do you own the entire house and thus have control over the entire job ? And have you read of 'Flanking Noise ' for which there are lots of references if you do a google search ..thus ..

noise defined, What is Noise?.


The older the house and the cheaper ..er, beg pardon, the most Inexpensive .. the conversion the more time and trouble sound damping is likely to be ... and the more Expensive of Course. Note that the term 'Sound Proofing ' that is often used is a bit of a misnomer in as much as true sound Proofing of an Old House is likely to be Scarily Expensive with most people being prepared to, say, settle for deadening footfall from above to below if they have to pay the bills for acoustic work.

Rugs on a hardwood floor to dampen footfall ? No , wont work - and I'm a fan of Persian/Iranian rugs ... off rug onto floor .. NOISE .. on to next rug softened footfall ... on to hardwood floor NOISE ..and so on.

Really heavy fitted carpet might help .. but thats not what you want to hear is it? And then theres still flanking noise.

A more complete Description of your house and a budget for the job may help the Experts to help you but be warned that a solution is unlikely to be cheap.
 

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