Sound transfer between floors

[Coolhurst]

Not sure where best to post this so thought I’d start here…

Simply put, in our recently completed extension we can hear noise transmitting between the floors very, very clearly. People chatting, the noise of the curtains being drawn along a metal curtain pole sounds like they’re in the same room etc. This ground floor room itself is a large (approx., 32ft x 12ft) single area so I’m not sure if this is creating some type of amplification. In fact, the sound actually feels like it is coming through the wall cavity!

The construction did bear in mind some noise abatement measures, namely 100mm acoustic sound slab consisting of Rockwool in between joists. The floor itself is 22mm caberwood and the ceiling below is 12.5mm plasterboard. We also laid extra thick carpet and underlay to the upper floor.

Our builder is flummoxed, the structural engineer can’t see any issues with the build spec. and our planning officer popped in and was confused as to the ‘why’.

My question is: are there ‘sound consultants’ that advise on domestic builds (I’m assuming there are)? I'd like to see if we can identify the 'why' and then what we can do to solve this mystery. Google seems to throw up large-scale consultancies which I doubt wouldn’t be interested in my small dilemma.

cheers in advance.

 

[chappers]

You could try Hepworth Accoustics, I have used them for testing and they are reasonable, but haven't a clue how much they would charge for consultancy.
I have used Graham Bowland at there Bristol branch, might be worth a phone call.

 

[KenGMac]

Coolhurst, good evening.

I am involved with a problem case as regards a similar issue of noise transfer.

I have opted to address the problem using a material called "Quietex"

if you think fit have a look at their Web Site.

In general terms sound absorption can only be achieved by adding MASS. In my case I recall the depth of this material [which is heavy] is 160mm, then there is the problem of getting the Quietex into place? that is a different story, and unfortunately needs to be carefully designed in as regards the total weight and the spans of the floor joists Etc. Etc.

I think that given the dimension's of the rooms involved in your case the Structural Engineer will have a load of shall we say "input" to tha additional heave loading imposed by the Quietex on such floor spans.

Suggest you also have a look at Sound Block Plasterboard ?

Ken.

 

[Coolhurst]

Thanks both.

Chappers - I've contacted Hepworth and awaiting a reply.

Ken - As you'll see the cross-section already has a sound slab in the form of Rockwool but I see what you are saying with the introduction of Quietex. Similar in theory I'd guess to a suggestion I once received to use sand in between joists. Sadly, with the extension fully finished it woujld be difficult to execute without major distruption.

BTW, I'm beginning to think this is more a 'flanking' sound issue.

 

[theprinceofdarkness]

I bet its flanking sound, that is sound coming down your internal walls because they are lightly constructed. I have a similar problem, bathroom above kitchen, the only sound you can hear is when someone slides along in the bath, resulting in a squeaking sound. Can't hear people on the loo. I packed 6" glassfibre very tightly into floor cavity. Did your builders do that with their insulation. Any small air gap makes a huge difference. i.e. if insulation is not overlapped at joints.
Frank