cellulose fibre spray for insulation

Recently while using this sites (members posts) to research the best method and materials to use to sound proof my proposed studio design. I came across a link that took me to an amazingly informative site that contained STC tests for many types of walls. While browsing through the many walls tested, I noticed one wall construction that I found particularly interesting. I found one wooden framed double wall contruction that exhibited higher than average stc level for lower frequencies. (page 351 of the ir761.pdf) When I examined the building materials used for this construction, I noticed that one of the materials used was cellulose fibre spray. As this material and construction method seems to improve sound isolation, I was wondering why people did not use this material / method to sound proof their studio's. I understand that rockwool in slab or loose form is easier, quicker and cleaner to work with, however, if sprayed insulation treatment offers superior sound isolation, then why not use it. I thought that it may even be a good idea to treat the insides of a double walls constructed frame in one go, in order to seal the frame to the highest level possible. (with the exception of perhaps allowing yourself a method of walking around the inside of the double frame in order to do the job). I also notised that the wall mentioned had insulation spray only on one of the double walls. I also wondered that if both sides of the wall were treated with the same or even more insulation spray, and a greater air gap was given than the 25 mm noted in the spec, that perhaps this double wall could reach even further stc levels. Anyway, just a question for those who are far wiser and experienced than I. Thanks to those who give help. info on cellulose fibre spray http://www.ehow.com/how_2140531_buy-cel ... ation.html

WE used cellulose fiber in the construction of Studio Oasis. The original building had standard trusses which we modified to scissor trusses which we lined with a double drywall layer. We then removed a couple of sheets of roofing iron and pumped cellulose fiber into the cavity, much easier than laying insulation batts throughout the ceiling space.

Really interesting. Thanks for info. Sorry if I haven't picked up on or read everything yet. I am just starting. I had a quick peak at the Oasis studio complex photos the other day. Looks awesome. A dream studio. Brilliant. P.S. I am afraid I do not yet understand woodworking / carpenters terms. So, not sure what some of the things you are talking about mean. Although, I hope to catch up at least in theory, in order that I may at least make the best choices. Cheers :-)

"I also wondered that if both sides of the wall were treated with the same or even more insulation spray, and a greater air gap was given than the 25 mm noted in the spec, that perhaps this double wall could reach even further stc levels." Yes it could. Getting the framing farther apart thereby creating a greater air gap is the easy part and is automatically beneficial. The minimum of mass-air-decoupling-insulation, either one of the four of these will produce better isolation with a combination of the four being the most helpful. The spray on cellulose is easy enough to do on the exterior partition. The problem with attempting to do the other side is that usually there is not enough room nor access into or out of the cavity for man and mechanical effects. You would need at least a 24 inch space to put an > equipped body< into that open area with gear to blow the back side of the wall. There is much data that recommends that mass-air-decoupling is the best starting place with insulation being beneficial but not so much that you would want to jump through all those hoops to install it to that extreme. As a thermal barrier on the exterior of the structure, it is a wise idea but beyond that, you would be better off putting your energy into other areas.

Sure, thanks for advice. However, i think that the design i am working on may still allow the insulation man access to the panel, as I am planning to put the insulation on the inside side of the wooden frame, rather than the outside. . This is because I am basing my plan on the non environment control room concept. So, I am making a wooden frame with a sheet of 1/8 inch ply on the outside of the frame, and plan to apply the insulation from the inside of the isolation booth / non environmental control room. . This should allow the installation engineer enough access to the inside of the wall with out too much problems. As, the walls of the inner room are designed specifically for absorption and not reflection, the design should be good enough for what i want to use it for. . Once the spray cellulose fibre has been installed, I plan to then cover the walls with PKB-2 and over that, acoustic fabric (or maybe even some trendy pyramids foam tiles (more because i like the way they look than for their absorption / diffusive qualities). Alternatively, I could always build the panels in modular format. Lay them flat face up, then get the insulation guy to install the spray cellulose while the panels are flat. Once the panels have been dried. I could then fix them together on top of the floating floor. And then fit the acoustic fabric and PKB-2 over the inside of the panels. Sealing as i go. :-) . The inner room aim is really to absorb as much sound as possible. So, I plan to provide as much absorption as possible. . I also plan to build an exterior wall around the inner room. This outer rooms purpose is different. designed more to trap and reflect than to solely absorb. . So, all this should hopefully be good enough for what I want to use the room for. . Anyway. Thanks for the help. Great help as always. :-)

All ya had to say was "inside out walls" :)

sure, sorry. I am really new to studio design and am not completely conversant with the regular terminology. I am not a studio designer by trade. Just through necessity. Although I think the concept of the non environment control room is one that should be more common, considering its usefulness and suitability for people with small rooms. Anyway, no offense meant. I am also dyslexic, so do ramble a bit too. Just how i was made i am afraid... fortunately my super powers make up for the things that i am not so good at. ;-)