Sorry... another Quietrock vs. Green Glue thread

Reasonable question. Let's look at the facts and some data:

#1 The Mass- When we're talking about Transmission Loss (reducing sound travelling from one side of a wall to the next), Mass factors into this heavily (sorry...) The heavier wall will be harder to move and will resist sound better. A sheet of standard 5/8" drywall from Home Depot weighs 70+ pounds per 4x8 sheet. Two sheets gives you 4.5 pounds per square foot. Nice mass.

#2 The Damping- Using a very small amount of a damping compound can reduce the resonance inherent to drywall. This is a good thing. However from a marketing standpoint, a drywall panel can be called "damped" even with an extremely small amount of damping material. There is no standard or guideline for how damped a panel has to be before it can be called "damped."

#3 The performance- http://www.greengluecompany.com/gree...mpedPanels.php $7 Standard drywall + Green Glue performs better than their top performing board, with the exception of their THX board, which is 1 1/4" thick and weighs 200 lbs...

#4 The Waste- There is an average 12% waste factor with drywall work. You can fill the dumpster with $7 a sheet drywall or $50 a sheet pre-damped board.

#5 The Cost- To get remotely similar performance (see the link) you'd have to move up several levels beyond the opening pricepoint Lowes board.

The bottom line is that you will always be able to field install a much heavier, much cheaper and much higher performance board than any pre-damped board available.

Regarding your $80 a sheet figure, Drywall is $7 a sheet = $14. GG for a board = $19.50. Labor runs $6.40 for the second sheet = $39.90. 12% waste of $7 board = $1.68 for the two standard drywalls combined. 12% waste of a $40 board = $4.80

Interesting pricing.

I looked at using the QR 545 board in my room (their top-of-the-line board). I compared that (via bids) with installing three layers of 1/2" drywall with green glue between each layer. The green glue approach was meaningful cheaper (by a few thousand dollars, actually) primarily because of the high cost of the 545 board and what was likely a tougher install with the 545 to get my desired performance (the 545 would have had to be carefully cut with a saw and we would have had to ensure no gaps--with the multilayer drywall approach we had a bit more room for error).

I went with the green glue approach and have been very happy with the results. I obviously can't draw a measured comparison with the 545 (since I haven't used the 545), but I do suspect that the 545 would have been a terrific performer. In the end the cost difference was just too significant and I got comfortable that the green glue option would serve my purposes.

I am not sure which QR you are looking at, but I would worry that anything less than the QR 545 would not perform up to the same level as a multilayered drywall and green glue approach. That is a gut feel--not something I can prove out.

I just finished drywalling my home theater a little over a month ago. I used two layers of 5/8 inch drywall with green glue in between. Now, after a month of the stuff curing and living with it... all I can say is I am more than pleased! In fact, it has turned out even better than I hoped. My wife and kids have even commented on how wonderful it is. I can be in the home theater room and watch football or a movie and my kids will be upstairs watching tv and neither of us can hear the other... granted, I also treated the HVAC and the floor joists, but the majority of the room treatment was the dual drywall and green glue. Would I do it all over again? In a heartbeat! Just my two cents... hope it helps. Thanks again to Ted for all the help and information!