Green Glue AND RC?

Overkill, or worthwhile? I'm thinking at least for my ceilings - as I may not be able to add much mass to the subfloor above.. just wondering if it's worth the extra cost/effort - or if it's 2x cost for an extra db or two. The RC would be on the leaf with the GG on it.. so 5/8->GG->5/8->RC->joists->subfloor

That's actually the best application if GG and RC together. :)

Awesome, thanks John! You think it's worth it do do on the walls, too? Maybe use RC on the drum-room side, and just GG in the control room? (to refresh your memory - in this design here: viewtopic.php?f=1&t=11741) "-)

Double walls are much more cost/NR efficient than single walls with RC and GG IMO. I've attached the other possibilities for the ceiling with Version 2 being the best IMO.

Thanks for the help, John. My plan WAS to completely decouple the studio rooms from the joists above and still may do this - the question about RC really came from another thread discussing the dead load capacity of my joists (see, in this section - dead load sanity check). I want to be able to add mass to the subfloor above. The possibility was brought up that while my joists are designed to handle 20psf dead load over the existing span - I need to talk to the manufacturer to find out if it can all be loaded to one side, or if it must be on the top/bottom. I suppose whether or not I can add mass to the subfloor - I'll still likely be better off completely decoupling the rooms. So - with completely decoupled rooms (version 2 in your doc above), does it still make sense to use RC on the ceiling and/or walls (let's assume GG is a given) ?

biggator wrote:

Thanks for the help, John. So - with completely decoupled rooms (version 2 in your doc above), does it still make sense to use RC on the ceiling and/or walls (let's assume GG is a given) ?

GG is not a given as it's two totally isolated structures. Similarly with RC - RC is only beneficial when you only have one structure as you do when you are dealing with floor joists in a basement ceiling or when you only have one single stud wall. When you have two totally isolated structures as in double wall with it's own independedent ceiling (as per version 2) neither RC or GG are required.

When you have two totally isolated structures as in double wall with it's own independedent ceiling (as per version 2) neither RC or GG are required.

So, while not required - is it still beneficial? Obviously Green Glue wants to sell product, so I take it with a grain of salt, but on their site here http://www.greengluecompany.com/wallTypes.php they show a complete double-wall construction with GG on both sides as 'ideal'. Now, the stuff isn't cheap - so if it's not going to help, I can save some $$... but if it'll give me an extra 6 or 8db, it may be worth it to me. I'm still trying to find out from Georgia-Pacific whether or not I can add mass directly to the subfloor above these rooms. My wife thinks I'm deeply over-thinking all of this.. she says 'just get it to a tolerable level, doesn't have to be SILENT' "-)

I'm not saying GG isn't going to help - but on a double wall system the RC adds no benefit. GG for your ceiling with RC is a good idea as I said in my first post. If you go to a double structure then weigh the extra db gained with the extra cost. An additional layer of drywall is probably cheaper than GG.

Thanks for all the help John!! I'm sure you hear it all the time, but this forum is an amazing resource. If you get a chance, check out my modification of the drawing you did for me (had to rearrange the rooms a bit) and let me know if you see anything glaringly wrong. viewtopic.php?f=1&t=11741 "-)