Mounting lights and other weighted items on Drywall with RC

[camistan]

From reading info on here, it seems it's not a good idea to hang anything of any additional degree of mass (weight?) to drywall mounted on RC. This post "somewhat" states this: (Post= Knightfly-April 8, 2004 about 3/4 way down)

http://johnlsayers.com/phpBB2/viewtopic ... over#10751

With this being the case, and with the fact that it's best to have little or no penetrations in the walls and/or ceilings, how do you hang "clouds", recessed lights, or other items of weight from a drywall ceiling that's hung on RC? I've seen some (clouds) hung by chains I believe, and others I couldn't tell for sure how they were mounted.

As far as recessed lights, I found this post concerning this topic:

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=1247

Rod answered the question, but I'm still confused as to how you secure the "box" for the recessed lights to the drywall? (drywall that's attatched to RC)

The only thing that comes to mind is to build a frame/housing for the lights, mount it to the ceiling joist, use 1 layer drywall (1/2"- 5/8" or whatever code allows) to put around the frame/housing, and caulk.

Doing this would make you "break up" the continuous strips of RC across the ceiling, and would force you to frame the RC around the recessed light frame/housing. Would this jeopardize the strength integrity of the RC?

(Hmmm...Maybe clouds and recessed lights are not in this "additional degree of mass" category???)

I put some pics below of the type of light "frame/housing" I'm talking about, along with pics of some clouds.

BTW I didn't continue this in my "ongoing" post as it seemed this would be a topic of some importance that may have got "buried" otherwise

Thanx
Stan

[knightfly]

Most, if not all, the pix you chose look to me like separate frames for inner leaf; these wouldn't need RC. All that would be required is a good seal, and probably putty packs around/behind the fixtures for more mass. You could also build a double drywall box around fixtures, provided they're rated for complete seal and still pass fire code.

If you MUST mount light fixtures on an RC ceilng, you can always run an extra row of RC where the light bars (surface mount) will go, or TWO extra runs of RC (one on either side of the row of recessed lights)

Make sure you research your light fixtures to make sure they are rated for completely sealed operation, and I'd also use X-core drywall for your ceilings just to be safe... Steve

[RickHatch]

I'm also wondering about hanging things like 703 panels etc. on the ceiling and walls of a room that is built with resilient channel.

Obviously you can't drill into the studs for support. Will drywall anchors into two layers of 1/2" drywall hold enough weight? I would assume that as long as you caulk the hole, that wouldn't interfere with isolation...

Or is it advisable to treat the RC as studs, and anchor the panels to the RC?

Thanks
Rick

[SittinIdol]

Anybody who's used RC got a thought on this?