TL data and metal studs

Thanks for the reply Steve :!: (Thread = 703 in Maryland) That's about 165 miles from my domain. I think I've found a Rockwool dealer that's a little closer, so I think I'm going to go with wall #343 in the NRC-CNRC Gypsum Board Walls: Transmission Loss Data papers. STC65 Now, this one uses 2 leaf construction = (2) 5/8" sheets of drywall with only 1-5/8" metal studs with 1-5/8" mineral fiber then a 2-1/2" air gap then the same for the other leaf (reversed of course). The TL data looks pretty good to me, considering it is a very compact wall to achieve that rating. Do you think it will really get these specs. in your experience :?: (With only a little better than an inch and a half of insul. on either side.) It would definitely make the walls less expensive. The only real problem I can see with that wall is fixing a door to a 1-5/8" frame. I guess I could double the track on the door side leaf and add another set of studs for the jamb. I dunno, sounds flimsy. What do you think :?: Thanks, TOM

puppypuree wrote:

this one uses 2 leaf construction = (2) 5/8" sheets of drywall with only 1-5/8" metal studs with 1-5/8" mineral fiber then a 2-1/2" air gap then the same for the other leaf (reversed of course). Do you think it will really get these specs. in your experience :?: (With only a little better than an inch and a half of insul. on either side.)

Tom, not only will it get those results - it DID get those results. You're looking at test data of an 8' high x 10' long wall assembly. HOWEVER - you may not acheive those total results depending on a lot of other things - construction of ALL assemblies would need to rerach those limits in order for you to realize the benifit. One of the reasons these walls work well is the " floppy" nature of the light guage metal studs. Rod

Sounds (pun intended) logical. Any idea about what to do with the door situation? TOM

First off, be sure to use a heavier guage steel (like 20 guage or heavier). Since you do have 2 1/2" of space, you probably could use wider steel for the jam. Are you making a soundlock or will the doors be back to back?

Thanks Rod and Aaron :) Steve has steered me away from the steel wall construction due to the moisture factor of my climate. I'm steering toward the soundlock design. Seems much more efficient TL-wise. (Main Concern) Now I'm back to the rigid fiberglass availability in my area. Thanks again, TOM

" Steve has steered me away from the steel wall construction due to the moisture factor of my climate" BTW, here's why - http://www.buildingscience.com/resource ... ldings.pdf Forgot where I found that til just now... Steve