Hi,

I building a TH in my basement. The area is 18 - 20' x 16' x 10' with three studded and insulated concrete walls and one wall that needs to be built.

I plan on building the new wall with staggered studs or more likely a double wall. Do I need to somehow "detach" the wall's top plate from joist? How would I do that?

For the three existing walls the top plates (double 2x4) are nailed into the joist. If there is a way to detach the top plate from the joist should I bother? If I do detach the wall from the top place, say by attaching the wall to the concrete, can I use less sound sound proofing?

Thanks,
Gary

At this point the walls are already attached to the joists, right?
So the easiest way to prevent sound transmission is to use a system to keep the drywall detached from the studs.
Many here have used the z-channel, among other methods, for doing this.

Yep, they are already attached.

If I couldn't detach the walls from the top plate I was going to use RC + DD + GG on the walls and ceiling.

For the new wall, I haven't found an "easy" way to detach the wall from the floor joists above. I found information on how to use RISC-DC04 clips to isolate every stud, but that seems both expensive and a pain. And I found an example of attaching a RC onto the joist and attaching the top plate to that. But, that doesn't see very sturdy. I was thinking of using multiple RISC-DC04 clips to attach the top plate to the joists. The rubber grommet part attaching to the joist and the flange part attaching to the top plate / stud.

Thanks,
Gary

Just build the wall 1" short of the ceiling joists and use RISC - 4 clips every two feet or so to connect the top plate to the joist (s).

You can see it in this photo in the upper right corner of the picture.

http://i208.photobucket.com/albums/bb308/mdrueen/IMG_0035-1.jpg

Yes, what Cathan said... RSIC-1-DC04 clips

The rubber grommet part attaching to the joist and the flange part attaching to the top plate / stud.

That's backwards. Look at Cathan's great pic for the proper orientation. I've used this method and it is plenty sturdy. Had it inpsected and there were no issues.

Thanks to all for the info. The picture is perfect.

Here's what I'm planning. A sanity check would be appreciated.

For the new wall: double stud with 5/8" DW + GG + 5/8"DW on each side, and all attachments to existing structure using RSIC-1-DC04.

For three existing 2x4 walls over foundation: 5/8" DW + GG + 5/8" DW + RSIC-V / hat track + existing wall.

For the ceiling: 5/8" DW + GG + 5/8" DW + RSIC-V / hat track + existing joist.

Leave 1/4" between DW and other surfaces and seal all openings with acoustical caulk. Seal power outlets, HVAC, etc. with putty. Use rope light and sconces in place of can lights. Get a good door and seal it well.

Am I missing anything?
Gary

The "new" walls in front of the foundation walls are by definition a double wall = decoupled. No need for clips and channel on any of your walls. I wouldn't bother with the 1/4" gap, either

Let me explain further, I might not have been clear.

I have three existing 2x4 walls with insulation in front of foundation walls, all three are attached to the floor joist above. The fourth side of the room is currently open.

For the existing walls I assumed I needed the RSIC-V / hat track to prevent flanking (wall stud -> top plate -> floor joist -> ...). Was my assumption incorrect?

I understand your comment about the double wall vs. RSIC-V / hat track. What I forgot to ask is should I use RSIC-1-DC04 on both sides of the double wall, or is the source side enough?

Thanks!
Gary

The three existing walls are what we would consider double walls. the foundation counts as one of the leaves in the double wall assembly. They could certainly use the DC-04, but do not need clips, as they are already decoupled.

Using the DC-04 is needed on the source side only. Good question.