Not another Green Glue Question - But I have some good News

Hi folks, I have decided not to use R/C on the ceiling and instead I am going with Green Glue. A lot more expensive but from all the research I have done it looks like its they way to go for me. QUICK NOTE For the Canadian's See my post in Building materials. Great news on Green Glue in Canada. http://www.johnlsayers.com/phpBB2/viewtopic.php?t=7295 I just finished the first layer of drywall in my my home studio. I am really impressed with the sound isolation already. I guess there is advantages to taking over a year to caulk, seal and prepare the walls and ceiling prior to the drywall, eh:) I think the bulking up of the floor above between the joists was a long and tedious job but well worth the effort. My question is a quick and hopefully simple one for many of you. Should I look at adding the green glue on my last layer of plywood for the floating floor before the hardwood as well. Like I said, The isolation is already pretty good so will it make that much of a difference in the end. Thanks for taking the time to help out. Vince

Thanks a lot Vince ! for sharing info on Gree Glue in Canada :D . I live in Montreal. 200$ a case is less than what it would cost importing it from the US. (customs fees, shipping ect...). Great news ! As for your GG in a multilayer floated wood floor it is something i am aslo wondering if it's worth it, we're both in the same boat i guess, ill keep you posted if i found an answer. Regards

Merci Eric Let me know if you find out. I have been reading your thread on your build. Very cool stuff.

orangenumerik wrote:

As for your GG in a multilayer floated wood floor it is something i am aslo wondering if it's worth it, we're both in the same boat i guess, ill keep you posted if i found an answer.

I will be applying a 3/8" layer of plywood and a 1/2" layer of OSB to my subfloor using GreenGlue between each layer and will post the results. I expect to do this in 3 weeks (after the 2 layers of drywall gut hung on my walls and ceiling (also using GreenGlue).

Jeff Chitouras wrote:

I will be applying a 3/8" layer of plywood and a 1/2" layer of OSB to my subfloor using GreenGlue between each layer and will post the results.

As per the information on the Green Glue web site, you should only have ONE layer of GG in any "sandwich" (typically the last layer), not GG between every layer. len

len-morgan wrote:

Jeff Chitouras wrote:

I will be applying a 3/8" layer of plywood and a 1/2" layer of OSB to my subfloor using GreenGlue between each layer and will post the results.

As per the information on the Green Glue web site, you should only have ONE layer of GG in any "sandwich" (typically the last layer), not GG between every layer. len

I appreciate the "head up" Len. I spoke to Ted at GreenGlue (VERY helpful) and he said that both layers with GreenGlue for floor construction would be superior because both layers act as constrained damping layers to dissapate vibrations. The following exerpt is from their site. "Multiple layers of Green Glue and drywall/OSB may be used. This option is also very effective against airborne sound by adding mass and damping to the weakest link of a typical floor/ceiling - the subfloor."

Yes, Ted is a class act -- I enjoyed my conversation with him earlier in the year. 8) I even coaxed him to come visit us on the forum, which he did. We need to bring him back though! ;-) And Len, you may have thought the "only one sandwich" idea came from then, but I think that's just us trying to save money. Having Green Glue between every layer of drywall all the time would definitely improve isolation... It would just be awfully expensive. --Keith :mrgreen:

Kieth, I'm sure I saw somewhere that GG should be applied only[/] on the last two layers. You may be right though and perhaps the idea was that if you had multiple layers (i.e., 3 or more) then [b]IF you were only going to use GG on one of the layers, it should be the last. Then again, at the time I was trying to digest so much information in such a short time that I just plain got it wrong. You are right though, it WOULD be expensive! len

I believe that applying 50% coverage on the back of the middle and final layers of a three layer wall/ceiling would outperform a three layer wall/ceiling with 100% coverage on only the last layer. Perhaps I'll do that with my three layers of drywall on my inner leaf! 8) --Keith :mrgreen:

Jeff Chitouras wrote:

orangenumerik wrote:

As for your GG in a multilayer floated wood floor it is something i am aslo wondering if it's worth it, we're both in the same boat i guess, ill keep you posted if i found an answer.

I will be applying a 3/8" layer of plywood and a 1/2" layer of OSB to my subfloor using GreenGlue between each layer and will post the results. It's been 10 days since applying GreenGlue in between each of two layers of 7/16" OSB placed on top of a subfloor made of 10" thick SIPs (Structural Insulated Panels- 7/16" OSB panels sandwich with a styrene/foam insulation in between ). GreenGlue works. Very Well. SIPs are something I would strongly urge NOT to use for studio building. Great insulation, Poor noise isolation due to low mass. Bad choice on my part but I was lucky enough to find Rod Gervais' book and GreenGlue. GreenGlue is expensive but if one is in a situation where you could not or did not build it "right" in the first place GreenGlue can save the day. GreenGlue says that the full isolating properties of GreenGlue will not become apparent for 30 days while the moisture content of the GrreenGlue is outgassed/removed. I can say that every two days since I have applied the flooring layers I can hear the difference in the increasing noise isolation between the outside and the interior of the studio space (interior dimensions are 27' x 18' x 14.5' peak of cathedral ceiling) and also with the "reverb" of the room when shouting, clapping hands etc. Even though it is expensive, using GreenGlue can reduce the need for adding more layers of drywall etc if you need to conserve space. Ted at GreenGlue indicated that using 2 tubes of GreenGlue on a 5/8" x 4 x 8 drywall panel will add the equivalent mass of one additional layer of 5/8. I also used GreenGlue between each of 2 layers of 5/8" drywall applied to the interior walls and cathedral ceiling of my exterior shell (I am building an inner room). I have not had pervious experience using layers of drywall as part of a 'mass-air-mass' structure so I can only give my experience in this building. Prior to adding the double layers of drywall (with GreenGlue betrween each layer) I could hit any of the walls and the reverb of the room was demoralizing. I had a metal ladder leaning against one wall and I could make it rattle but hitting an adjacent wall. After the GreenGlue drywall layers were applied (setting apart each wall/floor/ceiling from each other using the Corner Framing Detail/Gypboard Sequence as specified on this website/in Rod's book) I could hit the wall 3'/1m away from the ladder and the ladder would not rattle. (Perhaps not as scientifically rigorous a test but it was pretty effective on me...) The "reverb" of the room is now very reasonable for this stage of construction. Again, GreenGlue is expensive but if you factor in the cost of labor to hire someone to hang 4 layers of 5/8" drywall versus 2 layers of 5/8 with GreenGlue between each layer - equivalent according to GreenGlue - the costs come very close. And then there is the Time it will take to hang 4 layers, including backer rod and caulk for each layerto consider. (I enjoy doing a lot of things DIY but I have "issues" hanging drywall.) Anyway, my 2 cents. This product works.