Choosing fiberglass

Brillant, Steve, as usual... Now... Should i use Open Cell Foam Backer Rod, right? There´s any other thing to replace it -quick search tells me it will be hard to find it here-? BTW, Should i muld and tape every layer of gypsum or just la last one? Take a look the way my gypsum layers are going to be placed... Any other place to caulk? Thanks!

Backer rod's typically closed cell, doesnt' matter because it's not doing anything acoustic. Mud and tape each layer everywhere EXCEPT around the edges of the entire wall; backer rod and caulk the perimeter. In other words, caulk where the red lines are and mud/tape/sand where the question-mark is. http://www.loghelp.com/backerod.html The closed cell on the left is what you want; if you can't find it locally, you might be able to order on the net... Steve

Hey Steve, i found backer rod near home! ;) Cool! Yesterday i receive the Mason neoprene pads... Gypsum arrive next week. Finally, things start to happend. BTW, Why don´t you repost the drawings that you just posted here on the caulking sticky thread. They´re very informative. Next questions, after start framing..! Thanks man!!!

Started framing today! Check it out..! :D :D :D Check the circle on the pic of the pads... I´m floating the walls, but it´s REALLY hard to cross the screw right on the center of the pad... So, i´m put a couple of pads with the screws off center (where the red circle is), and the rest of it will be glued to the floor and the sole plate, to avoid unnecessary screws... Anything wrong with that? Anything else to keep in mind while framing? Thanks guys!!! Enjoying it so much, so far... :wink:

The minute you put ANY screws thru frame, pad and floor you've just eliminated any reason for using the pads at all. Please stop, and post a sketch of EXACTLY what you're doing - show floor, pad, base channel of the wall, screw, and anything else you're doing including what touches what, and where.... Steve

I understand your point Steve... I´m following the same approach as John on Snapper´s Studio... The sole plates rests over the pads, and i use screws to fix it to the floor... So, the entire frame is floated over the Mason pads... There´s any other way to do it? Thanks!

IF there's any metal-to-metal contact between your screws and the framing, the pads get bypassed and become pretty much worthless. If you have some sort of rubber isolators so that the screws NEVER touch the wall frame, and you don't compress the rubber too much, it will work... Steve If you draw a very detailed sketch of just ONE screw and the way it fits within the frame, pad, floor, and any rubber parts, I can tell you if it will work.

Here´s the idea... the washer prevent metal-to-metal contact... quite simple... The hole on the sole plate is wider than the one on the washer, so, even if the screw make a tiny movement, it won´t touch the sole plate. what do you think? Thanks! J.

To be safe, maybe more like this?

My god, that´s what i call a really smart plan! Thanks steve! btw, curiosity question... Does a room with corner bass traps performs better than a one without it (insolation-wise)?

I'm going to assume you mean "isolation", rather than "insulation" - as in sound control, or sound proofing - if so, the answer is no. In fact, a small amount WORSE sound proofing will result from nearly ANY acoustic treatment you use in a room - part of this is due to "3rd leaf effect", and part is due to the tendency to "turn it up" when it sounds good. According to actual test results, absorption in rooms makes almost no difference whatever in how much sound escapes the room - it only evens out the in-room response... Steve Glad you liked the isolator drawing 8)

Steve, i´m planning to use non rigid wool between studs, but i can´t find advise on how to "attach" the wool to the frame... The only way i can image is to glue the wool to the gypsum and screw the gyp layers to the frame with the insulation glued to his back... Any idea? Thanks!

I was referred to these... http://www.acousticalsolutions.com/prod ... _clips.asp

Impaling clips are for the more rigid board insulations; for steel studs and lighter weight insulation (like spun fiberglass) here is an effective way - http://www.naturalhandyman.com/iip/infxtra/infpop.shtm http://www.uline.com/Browse_Listing_275 ... +Strapping http://www.brandsonsale.com/ht-001275.html Use the punch to make a row of holes in the inner edge of each steel stud 1 foot off the floor, then every foot above that up to within about 6" from the ceiling - these holes need to be the correct size for pop rivets (first link) to which you will add washers - what you will be doing is placing polyester straps (1/2" wide is good) horizontally across the insides of your studs every foot of height. These will be fastened by using pop rivets and washers thru the inner flange of each stud, and the finished "grid" will keep your insulation from falling out the back of the frame; you should then use insulation that's just a bit thicker than your studs, so it will be kept in contact with the wallboard. The strapping will also keep the insulation from creeping down in between the stud frames. If you don't want to buy a punch, a proper sized drill bit will also work; just be careful not to snag your hands on the burrs around the holes - this isn't a problem with the punch because the holes are smooth. The punch will also work to make holes in the strapping for the pop rivets and washers that will hold the strapping onto the backside of your wall frame. An alternative to the punch for making holes in the strapping is to use a small diameter soldering iron and MELT holes in the strapping. If this wasn't clear enough, let me know and I'll do a basic sketch... Steve

Steve! I saved a little money and i wanna spend it on my studio 8) Right now, i have the brick wall, 8cm of air gap, 70mm steel studs filled with fiberglass and 2 layers of 5/8" gypsum. I didn´t put the ceiling yet, so i still can fill the 8cm air gap with more insulation... And here´s the question... I used 16kg non-rigid wool for inside the studs... Should i fill the gap with... a) 50kg/m3 rigid panels b) 16kg/m3 non-rigid batt c) leave it unfilled I wanna make the desicion now, before putting the celing, ´cause it´s gonna be hard to remove it if i need to add more insulation. What do you say? Thanks!

That would depend on some of your local conditions - Do you know what the typical humidity levels are? Any signs at all that you have mold problems? And, what method did you use to hold the 16 kG insulation into your steel stud frame? Are you considering a third layer of gypsum with Green Glue, or am I thinking of someone else? With 150mm block (solid) and 2 layers of 15mm gyp spaced as you stated, you'd be looking at the drums being just audible on the other side of the wall when you're at about 100 dB inside; another layer WITHOUT GG would put you at about 104 dB inside (TL @ 50 hZ of 49 dB, STC of 86 dB. However, IIRC your blocks were hollow; if you did NOT fill with foam as Rod suggested, you're STILL in trouble. IF you DID, you would have (wild guess here) still around 50 dB TL @ 50 hZ, with STC of around 78 dB ( not so steep a curve but still good) I'd think your floor and ceiling would be the weaker link in that case. If you can answer my first batch of questions, I'll see if I can answer yours about more insulation... Steve

Here we go... Do you know what the typical humidity levels are? Check this out... btw, we´re on summer right now, if it helps... Observed At: Buenos Aires, Argentina (December 9th) Elevation: 20 ft / 6 m [Scattered Clouds] 79 °F / 26 °C Humidity: 44% Sprinkle (not sure about this word, sorry): 55 °F / 13 °C Win: 18 mph / 30 km/h from the NO Air Pressure: 29.80 pul / 1009 hPa Visibility: 6.2 Millas / 10.0 Kilómetros UV: 3 out of 16 Clouds: 4000 ft / 1219 m 20000 ft / 6096 m (Above Ground Level) Any signs at all that you have mold problems? No. I don´t think so. What method did you use to hold the 16 kG insulation into your steel stud frame? Pressed by the sheetrock, with a little cut near the studs, so there´s compressed insulation between the gypsum and the stud, and the cavity between studs is fully filled. Check the draw. Are you considering a third layer of gypsum with Green Glue, or am I thinking of someone else? Not me. I don´t even know what Green Glue is... :oops: About the hollow bricks... 2 of the walls that i´m using was already there when we bought the house, and that walls was rendered on both sides. I couldn´t fill that 2 walls ´cause it was out of budget. The other 2 are filled. Should i treat those gaps in different ways?[/b] Thanks!

Here's Green Glue. Here is a recent discussion on StudioTips about the product. --Keith :mrgreen:

Thanks sharward! Can´t buy here in Argentina yet... Maybe i´ll order it to put it between the 2nd and the 3rd layer... :roll:

Steve, tomorrow I will receive my order from my wool retailer. I would appreciate if you could answer my last question before receiving the order. Thanks! 8)

Julian, sorry for the delay; every time I think my life can't get any crazier, it DOES... If you mean your question about the two walls you can't fill, maybe this link will help http://www.maconline.org/tech/materials/ssdata.html Keep in mind that those are all STC ratings, and don't mean much for LOW frequency (drums) - for that, your best bet is more MASS, no air space between it and the original walls. HTH... Steve

Thanks steve! It´s always nice to see stc predictions! ;) Anyway, my main question is how to improve insolation on the hollow brick walls and the filled-brick wall... Before putting the ceiling i can fill the 8cm air gap between the walls and the steel studs... I´m not sure if I should use... a) 50kg/m3 rigid panels b) 16kg/m3 non-rigid batt c) leave it unfilled Should i treat the walls using the same approach? Thanks again...

In-the-wall insulation - it's a toss-up between rigid 2.5 PCF and the 16 kG (1 PCF) stuff; the heavier costs a bit more and gives maybe 2 dB better STC, but no better LF results - the lighter stuff is best bang for buck for the insides of walls. And yes; a ceiling is pretty much just a horizontal wall, except that gravity helps keep insulation against the inner panels for damping, and helps the ceiling fall down easier if not built right :oops: IOW, what works for a wall will work for a ceiling, except for framing sizes and ways to hold insulation in place... Steve