I searched and everyone seems to be installing RSIC clips at 48" OC by 24" OC for ceilings. In reviewing the manual from Pac Intl:

GUIDE (http://www.pac-intl.com/pdf/RSIC-V_Installation_Guide.pdf)

with regards to ceilings, it only says that "Resilient Sound Isolation Clips (RSIC-V) shall be 48 inches maximum on center".

So that's what I did - 48" oc all the way around. Am I missing something? Should I go back and put a row 24" oc between each existing row?

Thanks in advance. Patrick

So that's what I did - 48" oc all the way around.

Did you follow the diagram for 24" x 48" or the 16" x 48" based on your joist spacing and place as shown or did you simply install at 48" in all directions?

Well, that's kind of my problem. The instructions for the ceiling do not mention anything but 48". So everyone is 48" apart (not quite, because my engineered joists are 20" oc so they're really 40 x 48). It's no big deal (and now makes sense) to go back and put a row every 24". I'm just a bit confused by the installation guide...

Thanks for the response.

You will actually have clips that physically measure 48 inches apart on the same joist and then 48 inches apart from that joist to the next joist starting at the first clip. What seems to get confusing is when you start to do the stagger. Before you buy more clips and install them, is there a way you can post a sketch of what you have actually installed so far? You may actually be OK if you alternated joists and rows like the installation diagram shows.

You certainly want them closer than 48" in at least one of the directions. I'm at this point in my build also. I studied this picture for a while until I could visualize it on my ceiling.
http://www.acousticalsurfaces.com/rsic_clips/art/rsic-v/wall-24.jpg

In your case, each successive joist will have a clip 20" away on a diagonal. On a single joist, the clips can be as far as 48" apart. When done per spec, this is supposed to hold 2 layers of drywall. Good luck.

After putting up my clips last night and re-reading my post, I see that it's not quite accurate. On the same joist, clips will be up to 6 ft apart, but within 22.6 inches of its nearest neighbor (the diagonal of 16"). Don't forget your "starter" courses at the edges. I found this spreadsheet somewhere on the 'Net, but for the life of me can't remember where. It takes all the guess-work out of ordering. Yes, I virus-scanned it first...clean.