Stud spacing for walls v/s STC rating
'Closely spaced studs result in a stiff wall, which is bad for STC. Increasing the stud spacing will improve STC rating'
Can someone confirm weather statement above is correct? The counter argument to this statement is that increasing stud spacing increases the amount of air gaps between studs which will allow for more sound to transfer through it. Stud being solid material will block the sound therefore, increasing stud spacing will reduce the STC rating?
What is ideal stud spacing ( closely spaced v/s increasing stud spacing) to improve STC rating?
“Closely spaced studs result in a stiff wall, which is bad for STC. Increasing the stud spacing will improve STC rating”…true statement…we haven’t tested that many different spacings, and I don’t know that spacing more than 24 in would even work to hold gypsum board….but 24 in spacing performs moderately better than 16 in spacing.
You are thinking of it a bit backwards: sound moves BETTER through the studs (lower STC) than through the airspaces (not the other way around). The studs create a flanking path—like a short circuit through the barrier
I was hoping Michael would comment on this thread. I found it helped to think of sound transmission through materials a bit like we think of thermal conductivity.
If you’re interested, I gave a presentation on acoustic control in multi-family construction that applies a lot of the principles in Michael Ermann’s book to typical wall and floor assemblies, which might make these concepts easier to remember for the exams. (I hadn’t met Michael when I gave the presentation, though. Small world — amber book totally saw me through this process). Anyway, the first 30 minutes or so are the most relevant for the AREs.
The presentation is free (I gave it for a manufacturer who makes a floor underlayment that’s used to improve a floor system’s ICC rating).
Your statement is correct. Studs transmit sound.
For the ARE, I think it's better to keep in simple! I wouldn't go too in depth about this one topic. Staggered studs (essentially creating 2 separate walls, with 2 layers of gyp on each side is the better.). More layers of gyp = less sound transmission. Insulation helps too.
Hope this helps!
Rebekka O'Melia, R.A., NCARB, B. Arch, M. Ed, NOMA, Step UP ARE 5.0 Courses
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