Recommendations? low-R value acoustic underlayment?
Is the Sound Solution underlayment the best option for engineered wood floating floors?
I like its low R-value (0.36), but the Sound Solution's STC and IIC are much less than one recommended by my GC, Silencer HD.
Sound Solution: 60 IIC, 54 STC 0.36 R, 7% compression max
Silencer HD: 70 IIC, 74 STC ?? R, 5% compression max
However, I can't find the R-value of the Silencer HD. Does anyone know? We're going over a radiant floor, so a low R-value is important.
And, is there meaningful difference in how solid an engineered floor would sound with each? I don't know if anything over e.g., 50 IIC is fine enough, or if the numbers still matter above 60.