Resilient Channels – can they lead to problems?
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I am about to drywall a basement ceiling. Sound control is a serious concern as the noise resonates all over the house from the basement. I have been looking at using resilient channels to hang the drywall.
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I have two concerns. I always understood that the sheet rock on the wall helps to hold up the ceiling. But if it touches in this circumstance negates the use of the resilient channels. So you are left with a gap that you caulk. How would you finish such a joint? You could mud it but that defeats the purpose of the RS.
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I have also read that RS have lead to many problems. True or marketing BS?
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http://industries.bnet.com/abstract.aspx?scname=Commercial+and+Heavy+Construction&docid=122459
Replies
If you have some time, you might want to brwose the AVS forum. It's an home-theater forum, with plenty of discussions on sound treatments (to improve how the music sounds inside the room) and sound control (to limit transmission), which are 2 aspects you want to take into account when building a home teather, If you are only interested in the sound control part, less reading needed :-)
http://www.avsforum.com/avs-vb/forumdisplay.php?s=&forumid=19
I'm planning to use a dual layer of drywall (different thicknesses, to ensure that their resonance doesn't add), with a sound dampening layer in between, and seals all around (including the door). Probably will go with Green Glue (http://www.audioalloy.com), but there's other viscoelastic materials I'm considering (not affiliated with Audio Alloy, and haven't tested it yet, so don't take this as an endorsement)
There's also plenty of links to resources on sound insulation (mostly for recording studios). I guess I can summarize what I learned in 3 sentences:
- Decouple the room you want to insulate (staggered studs, resilient channels, room inside a room, dampening materials on the walls)
- To stop sound (esp low frequencies), you need mass and space
- Seal everything. A poorly soundproofed/sealed door can let as much sound thru as an open window. An insulated room has to be seen as a system: it only works as well as the weakest link. Don't forget HVAC, light cans, etc
As far as I can tel, resilient channels are ok, but only if the people installing them truly understand how they work. Screws that bridge the drywall with a stud, or drywall touching studs, pretty much make them useless (well, much less effective). Leave a gap all around, and use plenty of acoustical caulk (a fancy name for caulk that never dries hard).
Dual layer of drywall with dampening seems much more effective, not much more expensive, and less prone to installation problems
Try the term :sound attenuation" on Google for info.
Personally, I have installed channel on many a basement ceiling with no problem.
If you had not planned on it be sure to use 5/8" gypboard on the ceiling. In fact you could use two layers of 1/2" installed perpendicular to each other. Sounds like you want to keep basement noise from the rest of the house. Most of mine were trying to keep the basement quiet from up stairs. No difference really.
If it happened to be a stud wall then I have built the studs to offset so the gyprock on one side did not hang from the same supports as the rock on the other side. Two walls, two membranes. Sound makes the rock vibrate on the wall but is muted from transmitting that vibration to the rock on the other wall because of the offset studs.
In your basement, screw the acoustical channel to the joists (coarse thread). Do it perpendicular to the joists. Screw the ceiling rock to the channel. Make sure these screws (fine thread) are not too long. They just have to go into the channel (steel). If they are too long there is decreased isolation because the screws could go through to the joist and thus transmit vibrations.
Normally the wall rock WILL give the ceiling support around the edge. Not in this case. That was developed in the days of dry wall nails anyway. Screws have much greater holding power than nails. So leave a 3/8" gap between horizonal ceiling rock and the vertical wall rock. I caulk it shut. You really don't have to paper tape the corner. The caulking can be knifed smooth and then textured. The appearance is almost the same. If you want to, go ahead and tape it too. Not much sound is going to travel from your acoustically hung ceiling rock and the mudded paper corner.
Let's see. Where did I leave those earmuffs? Tyr