Construction Details

Here is the first of some CAD details I hope to complete in this millenium - Tried to post this one at HR in answer to a Q there, but they only allow up to 64k, this one's about 96... Steve

Note that whichever way the sound tries to get in or out, there are ALWAYS TWO, and only TWO, centers of mass separated by ONE air space, in the way. (Thou shalt not use ONE, nor shall there be THREE, but only TWO - neither shall there be five... ) OK, no more blatant Monty Python ripoffs... Steve

Steve, thank you, thank you, thank........ You're a legend! Just what I needed and hope that many others will find it useful. I just have one question: Is there a certain amount of air gap between the frames you would recommend, or is it just purely up to you and space limitations? Thanks so much Steve

Cool Steve - your drafting looks great and I found it simple to follow. May I question one thing. You are using staggered studs sitting on a 6" x 1" base plate. Why not use the normal double wall system and float the inner wall on the inner floor i.e. room within room. Also the joists would sit on bearers before the cement blocks. ;) cheers john

John, exactly my thoughts after having a second look at the drawing...instead of having the celotex between the inner wall and the floor to avoid hard contact between the two, why not just sit the inside wall frame on the floor.... :? ...right??

something like this I thought...???

don't know why the stumps are not showing, but just imagine they're there :)

Guys, that was just a drawing I did for one of the guys at HR, who is building a shed on skids in his back yard for a rehearsal area. I figured if he moves it, the staggered stud approach would be stronger. As I get more stuff drawn I'll post it - John, I agree there's better TL to be had with true double walls, floating everything, etc - that particular drawing isn't something I'm going to build, just an answer to one person's problems that I figured others might find useful. It was also kind of an experiment to see how well my approach travelled over the net. I'm still drawing in Generic Cad, exporting to DXF, loading that into Autodesk's Quick Cad, then saving that as a JPG - I know it's convoluted, but it's still faster than learning a whole new proggie when mine is almost an extension of my frontal lobes by now. I did have one person ask for larger text, he couldn't read it - hafta look into that one... Steve

I built my exterior walls very similar to your drawing. I don't know if it would be a good idea to use a wider base plate, of course, it HAS to be pressure treated. Pressure treated lumber is VERY heavy! You also have to put some kind of base plate seal between the foundation and the bottom of the pressure treated base plate. It comes in rolls, and its kind of a neoprene/cellular stuff. I have NOT seen it come in rolls wider than 6". Something else to think about is that door frames, for external doors are not going to come wider than 6". And even to get THOSE, its a special order. So a wider base plate means you're looking at some really funky trim out or a custom built door frame. $$$$ CHA-CHING! Also consider the fact, that your door headers are going to have to be "Glue Lam's." To construct these, you use (3) 2x8's and sandwich (2) 1/2" strips of 8" wide plywood between them. That gives you a total width of 5 1/2", the width of your base plate. Use a wider base plate, and you're looking at a heavier door header too, depending on the span of your door, that may or may not be a good thing. (It can actually get too heavy that its not supporting the "criple studs" above it properly.) I built my walls in basically 10' sections with a 2x6 base plate, 10' staggered studs on 16" centers front and back, and a 2x6 top plate. It took 3 people to lift it up and position it over the foundation tie downs, and that was with NO exterior sheathing on it. To brace it or rack it square, I just used lumber on the outside set across it diagonally. The point here being is that the beefier you make the framing, the heavier its going to be. Naturally. Just keep in mind that you'll actually have to erect this thing, and don't get yourself into a position that you'll have to employ a crane to tilt up your walls! This is kind of off-topic, but another thing that continually amazes me is how each stage of construction adds to the rigidity of the structure. You start off with a frame section on the ground, and its racked for square, but its still kind of "wobbly". Then you get it tilted up and braced to plumb, that secures it, but you find yourself hoping there's no high winds! You finish the perimeter and get them all nailed together, and that helps, but they still move some. Then you place the top cap, which overlap the corners and all seams, and you feel like "Wow! That really helped. It doesn't move QUITE as much. Then the roof trusses go up which kind of pins the top, and you start thinking, "Alright! Those babies aren't going anywhere!" The first layer of external sheathing goes on, and you finally have a pretty rigid structure, allowing you, for the first time to begin removing the temporary bracing. As the internal framing goes up, it finally begins to feel like the rigid structure its supposed to be. And finally, as the internal sheathing is placed, you get the feel for how massive and sturdy your structure really is!

Michael, I know what you mean - it's hard to believe at some of the intermediate stages that it would take more than a knat's fart to blow the whole thing down - As I mentioned earlier, that particular drawing was done for one of the guys at HR, not for me. I'm planning on ICF constructed outer walls with 6" concrete and 2-3/4" foam each side, then couple layers of wallboard inside that, probably 6" air space then 6" steel studs/2 more layers of wallboard, etc - all inner walls will be steel stud and drywall, except where specific wall treatments don't work as well - that should keep things light enough to be doable. If I really needed a crane, I might be able to use my backhoe - except that my walls will be 16' high, and the middle joint on my hoe sits about 12' off the ground... Anyway, here's the next installment for the HR guys, hopefully they are easier to read... Steve

And, a close-up of the same, showing caulking locations...

Those drawings relate well Steve - even if it's long and convoluted way of getting them :):) What I can't understand is why use resilient channel when you are building a staggered stud wall (which achieves the same) ?? It's sortta double wammy!! cheers john

"What I can't understand is why use resilient channel when you are building a staggered stud wall " - John, you could leave out the RC but from what I've read, staggered stud construction by itself, while better than straight stud walls, could still be helped with RC on one side, considering that the top and bottom plates/caps are common to both sides of the wall, and that wood studs are stiffer and will de-couple less than the thin steel ones (for non-load bearing walls) I was under the impression that using steel studs negated the need for RC as well, til I saw examples in the USG handbooks of using RC to improve steel stud drywall construction by 2-3 dB. (I'm not sure, but that MAY have been a load-bearing wall using 6" heavier steel studs, whose extra stiffness would benefit from use of RC for extra decoupling) The things that seem to make the most difference in TL (assuming a double-leaf wall) are mass, de-coupling, air gap, and dis-similarity of inner/outer mass, not necessarily in that order. (Oh, and distance from the source-of-course - inverse square law, an' all that... :=) To top off the "moot point" scale (in a way) the person at HR that I originally drew this stuff for, is having "sticker shock" and may not build that way after all. Still, I think having a complete set of drawings for different types of construction is a worthwile project so I'll keep working on drawings with explanations, posting when I'm happy with each set. If anyone is in need of a PARTICULAR detail, feel free to ask - I'm not close enough to ground breaking yet that it matters what I draw next... Steve

knightfly wrote:

If anyone is in need of a PARTICULAR detail, feel free to ask - Steve

I will...again...sorry :lol: :lol: As I said before, I've no great knowledge about building framed walls, so my question is: Do the wall plates have to be common for both frames (inner+outer) when building staggered stud walls, and is there anything similar to dead men invovled when not using brick?? Do you have to tie the frames togehter? I know these are probably dumb ?s, but I'm not sure, so I'm asking :oops: Also, what's better when putting insulation itno the floor: -Insulation touching the floor or -An air gap between the two as shown in the drawings above? thank you all very much

oops!

Sen wrote:

knightfly wrote:

If anyone is in need of a PARTICULAR detail, feel free to ask - Steve

Do the wall plates have to be common for both frames (inner+outer) when building staggered stud walls, and is there anything similar to dead men invovled when not using brick?? Do you have to tie the frames togehter?

I don't know what you mean by wall plates??? What do you mean by "tie the frames together"? Do you mean adjoining adjacent 10'-12' wall sections? If so, what you do is make sure the last stud in one section is on the same side (preferably on the INNER, but its not crucial) as the first stud in the next section. You nail the wall frames together at that point. Also, when putting on the top cap, you make sure it overlaps at all corners, and spans all seams at joined wall sections. I can post a pic if you don't understand....

I think what Sen is referring to is plates, as in plates and caps of the stud frame. The staggered stud wall, by definition, uses common (but wider) caps and plates - at least 2x6 horizontals (caps, plates) with 2x4 studs. Keep in mind, Sen, that this is NOT the best soundproof wall you can build - the next level up would be totally independent frames for each mass center to attach to - outside of the outer frame, and inside of the inner frame (unless you're building John's inside out wall) - this type of wall would have SEPARATE plates and caps for each half of the wall, inner and outer - that gives better isolation, since there is no common framing member between inner and outer leaves of the wall. As to inner and outer frames being tied together, you don't want to do that with anything rigid as that will partially destroy the independence of the two masses. There are companies that make/sell acoustic braces that use a rubber joint surrounded in steel - naturally, I couldn't find the link when I went looking. Fell asleep twice trying to write this, guess I better get some sleep... Steve

knightfly wrote:

I think what Sen is referring to is plates, as in plates and caps of the stud frame. The staggered stud wall, by definition, uses common (but wider) caps and plates - at least 2x6 horizontals (caps, plates) with 2x4 studs. Keep in mind, Sen, that this is NOT the best soundproof wall you can build - ...

That's true. I wont refute that. BUT... the cross-sectional area of the sole plate and top plate is so minimal compared to the cross-sectional area of the stud wall that any sound transference from the sole plate to the stud, and thru a triple leafed wall is going to be negligable. Additionally, the sole plate is held SO rigid against the foundation that its doubtful (at least to me) that it would resonate at any discernable frequency. A double exterior wall is definately better for isolation, but the costs go up considerably. And if you're using a vaulted ceiling, the degree of construction complexity increases greatly as well because the interior wall would need to be a few inches taller, and the top stud would need to be cut at the pitch of the ceiling. And you STILL have the link between the 2 walls at the truss. Now, what you can do, or at least what i'm doing, is have a "belt and suspenders" approach! :) I have a staggered stud exterior wall, and a separate interior wall! This is limited to the control room though. This puts this room in essentially compleate isolation.

Michael, first of all cool pix - are you getting close to "rockin' the house", or does it just look like it? Bought that "full auto" screw gun yet? As to your comments on staggered studs vs dual wall - "And you STILL have the link between the 2 walls at the truss" - Not in the design I'm working on... I agree completely about the complexity, and am working on a set of drawings (as I design them) to (hopefully) simplify that type of construction while maintaining two (almost) completely separate mass centers everywhere between inside and outside. I'm probably being optimistic when I say that this could take a while... I have to disagree with your statement - "any sound transference from the sole plate to the stud, and thru a triple leafed wall is going to be negligable" - As near as I can figure out from charts of actually TESTED wall construction, there is a difference of about 9 dB - refer to the chart John posted here on march 01, re the STC 63 wall on the right - http://www.homer.com.au/phpBB2/viewtopi ... 86&start=0 vs the SAE chart on STC - http://www.saecollege.de/reference_mate ... 0Chart.htm In the SAE chart, check the staggered wood stud with insulation and two layers of wallboard at STC 54. (Essentially the same construction, only difference being staggered studs/common plate/cap vs separate stud frames) To me, 9 dB is about the same as putting the sound source 2-1/2 times as far away (which I would dearly LOVE to do with both my neighbors, since I can't talk the Lawnmower man into shredding Mr. "Dumber than his Dogs" and then turning the mower on himself) From your earlier comments, it sounds like you don't need as much isolation as I do. In your case, I'd be going for the best method that's actually DO-ABLE without having even MORE stress attacks than you've already been through. In MY case, however, if I shoot for enough isolation that I could target practice inside the studio with a .44 magnum at 2am without the neighbors (or my wife) hearing the noise, it should be just about the right amount. (Might be kinda hard on some of my condenser mics though... :=) I think it comes down to each different situation (needed isolation, available cash, time, etc) requiring a different approach, more than anything... Steve

Steve - I haven't bought that "full auto" screw gun yet. I'm still a ways off from sheetrockin'. The electrical and HVAC needs to be roughed in still. And the live room wall needs to be framed up. There's also a little closet that for storage that I haven't started yet. That'll end up being part of the live room wall... and insulation needs to be placed, and... and... and... There's SO much to be done! I spent the last day and a half hauling construction debris off to the dump! Five pick-up loads worth! It got to the point where I was moving junk from one room to another. And my yard, although hidden from any neighbors, had crap stacked up against the fence knee deep! That was REAL hard for me to deal with, because I have this "park-like" back yard. At least, I used to, before it turned into a construction site. :( So, time to step back, clean up and re-group. Re.: The walls. Fair enough. Maybe I'm missing something though: The staggered stud wall, with triple leaves gives an STC of 61. The double wall with triple leaves gives an STC of 63. ?? But you DO bring up a really valid point. And that is, Just HOW MUCH isolation do you need? For ANYONE contemplating ground-up studio construction, you have to answer this question before you even begin design. You could guess (not a good idea) or go with something that SEEMS reasonable (still not a real good idea) or, you could chart the noise on your site before you begin. Rent a dB meter, make sure its calibrated, and take measurements at regular intervals for a period of at least a couple of weeks. Graph the results, look for a high mean, and use that as a basis for your design. The complexity of construction that I spoke of earlier... I forgot to mention that if your walls are not perpendicular to the trusses, which, unless they are exterior walls, they wont be, then you'll have a compound mitre at the top of the wall if you have a vaulted ceiling. Difficult to frame up unless you know what you're doing! I JUST heard from my supplier. My front exterior door will be delivered tomorrow!!!! Of course its a raw door and it'll have to be stained and well oiled, but, hey, its on its way!

you sure have taken on a big project Michael. I bet you are fit!!! It will be worth it - just keep dreaming of the day when you sit in your new control room. :):) cheers john

Yeah, it is a big project. I've lost about 15 pounds since I started this! Gonna have to buy all new pants as the ones I have now are too big! As long as SOMETHING happens everyday, I'm happy. :D I REALLY want to hear that big ol' grand I have in the live room! Which reminds me: With your permission, I'd really like to use the "variable absorbers/diffusers" you had designed for Left Bank, but I can't find the pdf files you used to have posted. I'm sure I can do a really good job building them; custom joinery is right up my father's alley as he's quite the woodworker.

Thank you guys.... Steve, you understood what I meant, and thank you for your answer... Michael, your works are looking really good...eventhough it sort of scared me a bit...It's like: "How the hack do I get to that stage :lol: :lol: ?" hopefully in the near future... thanks

Michael, agreed with just about everything you said. The comparisons I meant were with two layers of 5/8 rock each side, of either staggered stud or separate 2x4 wood stud frames. With insulation, the 2 layer staggered stud comes in at 54 dB, the separate frame at 63 dB . That's the 9 dB difference I was referring to. Just for clarification (and so you don't scare me talking about triple leaf walls) I'm defining a LEAF as ALL the mass that is on one side of a frame whether there is one layer or three, a LAYER as one thickness of paneling, and an air gap as any area that doesn't have a hermetic seal interrupting it (insulation doesn't change an air gap into two air gaps) I'd love to hear your piano in that room when it's done too - bet it'll be sweet... Steve

Ahhh... LEAF and LAYER. I must get my nomenclature down correctly! Now I understand. I think. :?