more on soundproofing a room.

Hi all.

About six months ago, I had the carpets up and put two layers of ''T50'' soundproofing over the chipboard that is my floor.

This is a product with better soundproofing qualities than Lead, and almost 6mm of it covers my floor.

For the audiophile in me, I was pleased to note better bass definition due to the properties of the added material.

From a soundproofing point of view, an initial thumbs up for success has been followed over a long term by the obviousness that I havent gone quite far enough.

Here is the product

http://www.customaudiodesigns.co.uk/acoustic-membrane.htm

The carpet must now be lifted again, and further product put in place to prevent sound transmission through the floor.

I have to accept that there may be some soundleakage through shared walls, but I dont think we are quite at that point yet where this is the only remaining factor.

Reading around the topic, a floating floor seems the most obvious solution.. essentially chipboard 18/22mm - with a membrane underneath to seperate it form the existing floor.

This will (unfortunately) raise the floor by about 26mm all in, but can't be helped.

Has anyone any experience of installation of floating floors ?

I am thinking inexpensive tongue and groove chipboard (wickes, £5p/m), with a foam barrier (not sourced yet).

If you have experience of the installation of floating floors/soundproofing floors please do send a PM.

Thanks!

 

Just bare in mind the compliance of the foam should be correct for the weight on top of it, such that the resonant frequency is around 10Hz or below. Most manufactures of this sort of foam provide a chart to show weight vs. frequency per square area.

I'll PM you some info in a while.

 

cheers thanks Simon.

After a budget foam rather than something expensive per metre. Was even considering using acoustic mineral wool which must be pretty cheap (a certain site reccomended it). . although I have no prices for this option yet.

 

Remind me, what's the rest of the floor build-up? Is this a party floor with a neighbour below?

 

hi andy

its a period conversion, now flats.

Walls are brick,

floor is pasterboard ceiling, joists, thermal filler (cant change), chipboard floorboards, 2 x layers of T50, carpet.

 

You won't like this, but the best way to get the floor performance up noticeably is to isolate ALL the floor layers from the actual joists. You basically need an engineered resilient support on top of the joists and the support needs to be loaded up with heavy floor layers to get a low natural frequenmcy as Simon suggested. We would use a T&G, 19mm Plank plastrboard, compressed cement sheet and the T50 loaded vinyl products.

With the floor you have, there is most likely a nasty drop off in performance around the 100-150Hz region. It's inherent in this type of floor unless the floor or ceiling layer is resiliently supperted away from the joists.

 

yeah, would have done it differently if could have started again. I jumped in too soon hoping to achieve it all with just the T50 layers.

thing is - the t50 is bonded to the floor now, and 2 layers cost £700. It's now therefore ''whats best in circumstance'' ?

funnily, it's not any specific frequency getting through and not others - it's either nothing at medium volume, or whole music makes it intact at high volume.

 

I know just the stuff you need I installed some in my hifi room last year and it was 100% successful in the removal of all noise previously transmitted from my hifi through to the room below. it's er, or you know, that whatchamacallit.














closed back headphones... that's it.

 

Funny you should mention this..
What would be an effective way of preventing/reducing transmission to the floor above(flats/plasterboard ceiling/ t&g floor above?
Thanks
Cooky

 

Hi Cooky

Ive had several conversations with custom audio design about it, and its reflected in what Andy is saying, I think he does this kind of thing for a living.

I would read aroudn the sound proofing pages on the custom audio designs website.

It s a mixture of decoupling joists from the plasterboard, using the right cavity fill, decoupling the joists from the floorboards, building a floating floor.

It seems easier to attack the job from above rather than beneath to me.

 

You can treat it from the underside but it means suspending another ceiling below the existing one. You lose ceiling height and might cover up nice Victorian cornice... The bigger the cavity, the better the low-frequency performance, minimum caivty should be around the 300mm mark to keep the low-frequency performance.

These sort of mounts are very effective when loaded up with 2 x 15mm Gyproc Soundbloc. Scroll down to "Ceiling Suspension Systems" and look at pdf under CDM-CCS.

http://www.cdm-uk.co.uk/building_solutions.html#ceiling_isolation

 

Best way to think of sound insulation is three major stages:

i) for a 'single' layer (that can be made up of multiple layers of different materials sandiwthced together) performance is clolely related to total surface mass (kg/m2).

ii) the next move up the ladder is to a dual layer + cavity build-up where each layer is coupled together structurally by a common support element (i.e. stud or joist). For the same overall kg/m2, should get a 5 to 10dB jump in sound insulation performance compared to i) but can create some negative issues at low frequencies unless large cavities + heavy layers are used.

iii) next major upgrade is to isolate either the floor or ceiling layer from the common support element. You then get a 5 to 10dB jump in performance for no extra weight.

You are at stage ii)

 

Cheers Andy/Chris, that's what I was after.

My brother is in a ground floor flat and can only do something about this from his gaff.

Cooky

 

Cooky,

You can definitely improve it from the underside. Depends how good the existing floor is though. If it's a basic floor as you say, improvement would be massive once you go to a heavy plasterboard ceiling on engineered suppot system. It's actually not that hard to install yourselfm (two people at least to lift boards). The mounts come in two basic types and the supplier tells you what type to use and at what spacing based on the ceiling weight. Good starting point is 2 x 15mm Gyproc Soundbloc. That can be hard to lift as a single sheet so another build-up is 1 x 19mm Gyproc Plank (comes as 600 x 2400 sheets) + 1 x 12.5mm Gyproc Wallboard (much lighter and easier to work with than 15mm Soundbloc). Or 3 x 12.5mm Gyproc Wallboard. Stagger the joints.

To reduce bhe loss of ceiling heights, you are better off taking down the existing ceiling, adding mass/insulation between the joists as close to the underside of the floor above, and then installing the new ceiling on mounts below. That ceiling only has to site down below the joists the depth of the mount itself rather than 300mm below existing ceiling.

 

This is pure gold Andy thanks a lot, I shall pass this on to me bro'.

Cooky

 

latest,

been advised to put 2 x layers of acoustic fibreboard down (at right angles), and 3mm ply on top

all these options are coming in 300-400 ish materials, plus labour

losing hope! lol

 

What do they mean by acoustic fibreboard?

If you really want to push up the floor weight, try cement impregnated chipboard. That shit is seriously heavy... http://www.domesticsoundproofing.co.uk/soundproofing/cement.htm

If you can find someone that sells the product called Pyrok, it's the same thing but should be cheaper than buying from a specialist 'acoustic' supplier. http://www.euroform.co.uk/pyrok_what_is.shtml

 

sorry andy, meant acoustic plasterboard.

 

The Pyrok board will give more mass per mm increase in floor height compared to plasterboard (density 1300kg/m3 versus 850kg/m3) and no need to put the 3mm ply on top.

 

how much is it?

I cant find prices

the acoustic pasterboard is about £6 sq/m