new studio search for a concrete advice

Hi there again, Following are last discussion about the gypsum wall mass: me: "If the building can't handle the three 15mm of gypsum layers, is there another workable solution without compromising sound proofing? " Steve: "Only thing I know of would be using either Green Glue between two layers, or someone on your side of the ocean had another similar CLD coating, don't remember now who it was. " Eventually seems that my ceiling can't handle the three 15mm gypsum layers so I have to go with the second option to add a CLD coating between the layers. As the Green Glue is not an option for me here in the south-east of Europe, does a material like limp mass vinyl would have similar results? Are there any other DIY materials that can act as an CLD coating? If I use a CLD coating between gypsum layers, does the thickness of the layers should stay 15mm for both sides or the inner layer should be thinner? Dimitri

Hi Newtones, I don't know if this is an option, but you may want to email these guys as they are the UK and European distributors for Green Glue. http://www.rpg-europe.co.uk Just a thought, but they may well ship direct to you. Regards, Lou. 8)

I thought about that, but unfortunately delivery times are very unstable here in Crete. This shouldn't be always a problem, but because I am renting the studio space, time is not on my side and I have to get something going soon. Normally it takes minimum 3-4 weeks to receive something from abroad. Thanks anyway.

are you using CCTV for the drum booth it's a long way from the control room?

:oops: sorry re-read the top!!!

Yes, I am going to use CCTV for the drums. Unfortunately, it was the only workable solution I could find to keep a drum booth on the plan. Any ideas on my last post?

I am about to start attaching the gyspum boards to the studs but still I do not have a clear image of what I am about to do..so any help would be GREAT help. The situation goes like this: a) I am not using RC at all. b) I want to cover the perimeter of the exisitng studio's concrete walls with one leaf of three layers of 15mm gypsum boards (due lack of space between existing concrete walls and the new leaf / better LF isolation). No idea HOW to FASTEN the THREE LAYERS into the studs. Do I use FULL SCHEDULE fasteners for all THREE layers? Do I use screws all the way to the metal studs for the second & third layers? c) I am about to build a TWO LEAF WALL between Control Room & Live Room + Control Room & Vocal Booth. No RC here again, but I am going again for three layers of gypsum for each leaf (seperated leafs - 15mm of air gap between). I was thinking about 3 layers of 15mm gypsum for control room side wall (one leaf) and two 15mm plus one 12mm gypsum boards on the other side (second leaf). Am I correct to assume that the second leaf should have DIFFERENT MASS than the first? Again, how do I fasten the gyspum boards to the metal studs now that I have two leafs? Do I use FULL SCHEDULE fasteners for all THREE layers on both leafs? Thanks Dimitri

Yes, full schedule fasteners on all three layers. Yes, the fasteners must penetrate the studs... If wood studs, the fasteners (screws preferred) must penetrate the studs by at least 1". Therefore, you'll need screws of varying lengths. --Keith :mrgreen:

Thanks for the reply, Please correct me if I am wrong in the following: I recall reading somewhere that putting screws through the first layer and into the studs when mounting a second / third layer - therefore laminate the three layers together - that somehow I degrade the STC of the wall. Taking the above into consideration and with my limited knowledge on the subject, can I assume that fastening the first layer to the metal studs, then the second layer only to the first layer (not on the studs) and finally the third layer same as the second, would I partially de-couple the outer two layer from the studs, thus improve the STC? Should I also worry about the large number of screws going through the studs, if besides the first layer, the fasteners from second & third layer are also penetrate the metal studs? Would this increase 'flanking'? I have to point out again, just to be sure, that I am not using Resilent Channels.

Soundproofing is a constant balancing act, taking into account proven concepts, value, and safe/appropriate construction techniques. I think, technically, you're right that fastening layers of drywall to the studs is less theoretically ideal from a soundproofing perspective than fastening subsequent layers to preceding layers and missing the studs. However, gravity plays a big part in ensuring such a theoretical concept would be impossible as the walls would probably fall apart due to insufficient structural integrity. Two to three years ago, it was common here on this forum to advise using half the number of fasteners for all but the final layer of drywall. However, that advice (I think, and hope) stopped being given once I posted about my local building department's adamant objection to it, supported by most modern building codes. It is important to have a pretty solid grasp of conventional construction methods before venturing into a constructuon project that requires a significant amount of soundproofing. While it is true that many conventional construction methods are disasterous for soundproofing, such a basic foundation of knowledge is critical in understanding what modifications can be made for soundproofing's sake that will not compromise the structural integrity and/or safety of the build. Also, regarding dissimilar thicknesses of materials on the leaves -- while there may be a very slight benefit in doing so for some frequencies (forget STC!!!!!!), the fact is: increasing the thicknesses to be the same throughout increases transmission loss performance on the pesky low end where the problems are... In addition, the simplicity of working with one thickness of material can't be undervalued. --Keith :mrgreen: