House extension using SIPs? Sound insulation challenges??

Hi I am trying to find an affordable way to undertake a drum practice studio build, and posted previously about finding a portable building to put in my garden and reinsulating it. I'm now looking at the more permanent option of a house extension using SIPs. This is much more cost effective than doing an extension using traditional building methods... But I wonder what level of sound insulation I would get with this? I'm guessing that the SIP wall could act as the outer shell and I could do a standard ' room within a room' design to improve sound insulation? There are some figures given in the acoustic certificate below, but I don't quite understand them http://www.sipbuildingsystems.co.uk/ http://www.sipbuildingsystems.co.uk/pdf ... ficate.pdf Any thoughts appreciated Regards

Using a set named H14225BA (it is described in detail in the second link) you would have Rw 60 (-2, -8) dB which will give you max 56 dB of SPL reduction for speech and max 50 dB of SPL reduction for traffic noise. This values would probably be lower because of flanking tranfer (? is it proper naming?). In these calculations I assumed -2dB from flanking. And probably it will be the maximum SPL reduction you can get using this solution because it already is two leaf system. My idea would be trying to add mass to each leaf but the overall effects would not be as good as it could be using conventional solutions. But maybe some more experienced people would write more.. - Mathew

Many thanks Mathew I'll get some prices and give this some more thought. Adding some layers of plasterboard to the inner leaf might make enough of a difference to make this option viable. Cheers

I am trying to find an affordable way to undertake a drum practice studio build, ... But I wonder what level of sound insulation I would get with this

For drums? Not enough. The figures they are quoting are similar to STC (which is a really lousy way of measuring studio isolation!), and the graphs show rather alarming performance for drums. For example, there is a very clear MSM resonance dip at around 80 Hz. Guess what the common frequency for tuning a kick drum is? :) In other words, that structure would give you less than 20 dB of isolation for your kick drum (18.4 dB on one graph, 14.7 on another...), according to their own graphs.

I'm guessing that the SIP wall could act as the outer shell and I could do a standard ' room within a room' design to improve sound insulation?

That would probably work, yes. But I would still put some more mass on that SIP outer leaf wall. There is some evidence in the graphs that it might be acting as a 3-leaf or 4-leaf system, since there seem to be multiple dips in the low end on some graphs. So I would add at least one extra layer of thick OSB, drywall or plywood to the inside surface of that wall, then build the inner-leaf in the normal manner. - Stuart -