If I was to drop a layer from a leaf. Example...two seperate stud frames, one with ONE layer of 16mm plasterboard, the other with TWO layers of the same how much would the airgap have to increase to compensate for one less layer?
In my potential design in the works, I have the room to have a substantial air gap, 8 inches or even more. Im toying with methods and materials that yield the best performance for the best dollar hence the question. It may well be more simple and cheaper to fill a larger air gap with insulation than have to put up more plasterboard. Yes, Im looking to isolate rock band with drum type levels. Thanks.
extra leaf layer v's air gap.
Originally posted at johnlsayers.com, topic 17278.
Very rough rule of thumb: If you halve the mass, you need to double the distance to compensate. In your case, you are reducing the mass by 25%, so you need to increase the gap by 25%. If you already calculated that you need an 8" air gap with the original plan, then you will now need a 10" air gap.
HOWEVER! That rule of thumb is only really valid over a limited range of distances and masses, and only if you are changing the mass on BOTH leaves at the same time: you always get optimum isolation if the mass is the same on both leaves. So to be certain, you really should do your calculations again, and figure if 10" is enough or not.
OK, so that's ONE side of the equation: What is the other side? How quiet does that have to be on the other side of the isolation? You have upwards of 115 dB in the room: what level is your goal on the outside? Isolating drums is the hardest of all to do... - Stuart -Im looking to isolate rock band with drum type levels.