I'm building 2x4 framed walls (double 5/8"+GG) on a concrete slab- I'm thinking it would be wise to put some kind of spring between the concrete and frame, as the ground literally shakes with the traffic that is half a block away.
I found this product:
http://soundproofing.org/infopages/vibrationpads.htm
It says it can handle 50 lbs/square Inch, I'm assuming this is it's max load, so i should aim for half that figure, no?
anyone used this product or have any better suggestions?
Neoprene damping options
Originally posted at johnlsayers.com, topic 14623.
Ouch! That's not good. You might be one of the few candidates for a proper floating floor, but doing that right is nowhere near as easy as some manufacturers of "isolation" products would have you believe. Here is a really good discussion of what it takes to correctly float a floor: viewtopic.php?f=2&t=8173 As you can see, it is not easy, and not cheap, and there are no magical products that can do it cheaply or simply. It will take some time, lots of careful calculations, and some money, but it can be done. Several people here have done it....as the ground literally shakes with the traffic that is half a block away.
No! That would not work at all! If you only loaded it to half its design loading, then it most likely would not isolate at all! It works like this: any resilient substance that you use to isolate vibration can be thought of as if it was a spring. It has to be compressed just right, such that it is at its maximum "bounce" when fully loaded. If you put too much load on it, then it "bottoms out", doesn't bounce at all, and directly connects the two sides so vibration travels straight through, unimpeded. And the same thing happens if you don't compress it enough: It doesn't bounce, and transmits vibration directly. Imagine taking a spring from the suspension of a huge truck and trying to use it on your bicycle: To such a tiny weight as bicycle frame, that "spring" is not a spring at all: it is just a chunk of solid steel. You have to load it with several tons before it flexes enough to act like a spring. In other words, at each point under your floating floor where you are going to have a "spring" (regardless of what it is made of), you MUST calculate the exact loading that will occur at that specific point, both for the dead load of just the structure itself as the minimum case, and also for the worst-case live load, including people, instruments, equipment, etc. Both of those figures (best case and worst case" must still be in the operating load range for the spring that you use at each location. And since there will be different loading at different points under your floor (the springs under the walls will obviously be taking a much higher loading than the springs under the middle of the floor) you have to calculate the correct loading at each point, and the correct surface area, and the correct material to use. so you have to be certain that you have the right load and right layout for your springs, because if even ONE of them is "bottomed out", then you blew it! Just one single point of failure is all you need to wreck the isolation of the entire room. The vibration will flank through that path, ignoring all the other completely. Just like a single hole in a water tank is where all the water will leak out of, regardless of how good the rest of the tank is. It only takes one weak point to wreck it all, so you have to be certain that all your calculations are correct (despite what some manufacturers try to tell you about how easy it is to float a floor). Finally, you have to do all of the above while also making sure that you have enough mass and air gap and damping in the entire system that the MSM resonant frequency of the floor is at least an octave lower than the lowest range that you need to isolate. So if you are going to be doing full-range music in there (rock, pop, rap, techno, etc), then you have to design it all such that the MSM resonance is below 10 Hz. Not for the feint of heart! And no, there are no shortcuts. The chances of getting it right purely by chance, without doing the calculations, are about the same as your chance of winning the lottery in fifty cities on the same day, when you didn't even buy any tickets! In other words, the chances are around zero. It can be done, but isn't easy. Read though that thread to get an idea of how to do this right. - Stuart -It says it can handle 50 lbs/square Inch, I'm assuming this is it's max load, so i should aim for half that figure, no?