Beginning construction in China

Posted: Sun Aug 10, 2008 9:51 am

I have a question regarding ceiling design. The books I have pretty much depict existing ceiling as standard American wooden houses, but since the space I'm using is typical all brick/concrete high-rise apartment, I'm not sure how to structure the isolation ceiling. I'm thinking of maybe something like securing wooden studs onto the existing concrete ceiling, then secure the anti-vibration springs onto the wooden studs, then suspend 4 layers of 0.9cm gypsum from the springs, with about 4" of glassfiber insulation between the gypsums and the existing concrete ceiling. Of course, the ceiling will not touch the walls, and the small gap between them will be caulked.

Does that sound right? If any of you experts can help confirm this design, I'll go ahead and draw it for the construction guys, then I can finally get cranking on the next phase of the construction. If there are any problems with my previous drawings, please let me know right away so I can change the design. Thanks!

Posted: Sun Aug 10, 2008 11:46 am

whenever it is possible to carry the ceiling on your walls - without the hangers - that would be preferable.

I would not do this like you suggest.

I would connect the hangers directly to the concrete itself - and then use them to hang either a 2x4 or 2x6 ceiling frame that I attach the drywall to.

You have to be carefully when sizing the hangers to calculate the exact load - any hanger in the middle will be carrying exactly 1/2 the weight of the span - while the ends will only carry 25% in the length of the wall - drywall ceilings at the wall ends parallel to the studs will generally impart no loads to the wall (due to the cantilevel effect - a hanger each side of your concrete beam I see below the existing ceiling will carry 1/2 the weight of the box plus 25% of the ceiling (assuming a center support is used for the ceiling in that bay).

In between the concrete beams - if you only have the 2 end hangers......... then the hangers carry 1/2 the ceiling load and 1/2 of the box loads at each end.

Also be careful if the room is not symmetrical to the beams - in that case you will need to calculate the individual ceiling joist loads to determine what they are carrying - and will have to size each isolator to fit that particular load.

Don't forger to include the weight of the framing itself in the calculations.

What this ends up meaning is that you will probably have to use a lot of different capacity hangers - and must make certain that they end up in the right locations.

As far as your walls go - if you use a continuous pad like you show - the chances are it will not load up enough to act as an isolator.

It really needs to be pucks sized for the load of individual studs.

Again this gets tricky.

For example - if you have a door opening and one of my super doors installed for isolation - then the hinge side of the door would carry the load of the entire dfoor - plus 1/2 the load of any ceiling load attributed to the ceiling - plus 1/2 of the wall load to being carried by the door jamb and the nearest stud - while the opposite side of the door will only be carrying the other half of the ceiling load plus 1/2 the wall load from from it and the nearest stud on that side of the door.

Perhaps 50 to 100 pounds on one side - and maybe 450 to 400 pounds on the other.

2 different loads - and thus the pucks will be totally different in design requirements and capacity. (Size as well as hardness)

This will happen throughout the walls - with different load requirements on bearing versus non bearing wall - and even on bearing walls between the wall middles and the ends.

Again - if this gets screwed up - the pucks will act as transmitters instead of isolators.

Too much or too little compression will create that.

I hope this helped.

Rod

Posted: Sun Aug 10, 2008 11:25 pm

Hooo boy. For a guy that flunked math twice in school as a kid (all I did was draw pictures and write screenplays in class), the complexity of this is daunting. I don't even know if the current design is the most effective, or if there are simpler designs that performs just as or almost as well, but without all the complex considerations.

I'm starting to get the feeling that I'm trying to achieve something that is too much trouble for a high-rise apartment and should just go for the most simple solution and live with the fact I probably can't get good isolation no matter what I do anyway? At some point, there's diminishing returns and I'm starting to feel that coming on.

Rod, I trust your expertise, and your suggestion for the floor was extremely helpful--it was not contained in your book and it made a world of difference in simplifying what I should do for the floor. Do you have other simple solutions like that for the ceiling or the walls? Forget about my ideas and drawings for a sec--they are just me struggling to make sense of everything, and if there are far simpler yet efficient designs, feel free to tell me to scrap them all and suggest something simpler/better.

Posted: Mon Aug 11, 2008 5:29 am

Here's the drawing I just did to visualize how I'd handle the annoying beams on the ceiling with two different heights. The pink is the existing concrete beams, the blue is the length studs, the orange is the horizontal ones for the sole purpose of covering up the beam that drops lower, and the green is the gypsum boards. If I can find the RC1&2 resilient channels here, I'll use them to decouple the gypsums from the studs (and if not, I don't know what I'll do). Glassfiber insulation will go above the gypsums.

Does this look like a good idea? I didn't try to work in the hangers for this design since I can't figure out how to do it without sacrificing ceiling height. If I drop below the lowest beam for the entire ceiling, I'd have intolerably low ceiling. Man, this ceiling is the hardest part for me to figure out right now. Help?

Posted: Wed Aug 20, 2008 7:52 am

Ok, here are some photos of the stuff I was able to find locally, but with no data regarding their optimum compression weight (we asked, and no one could tell us anything). The black one with the yellow edge--that's supposed to be made out of tire rubber. The others are all neoprene.

So, I'm wondering if there are other materials I could use besides neoprene that's very common and very easy to find out what kind of weight they should carry for good isolation?

Also, I can't find any ISO clips, and it looks like punching holes in a hat channel to make RC2 sounded like a bad idea when I asked. What else can I use besides RC2 or hat channel+ISO clips to decouple the gypsums from the joists/studs?

I can't find anything like these either:

Are there alternatives I can try--maybe rig more common construction parts together--like some kind of common steel bracket swith neoprene inserted inbetween?

I also realized that my drawing of the ceiling is wrong, since I need to have the joists go horizontal if they're to rest on the new walls like Rod suggested. So without redrawing it, the idea would still be the same. I'll see if I could redraw it showing the joists resting on the walls. Without any reliable data about the neoprenes, would I be better off not using any neoprene at all underneath the walls? What if I used some kind of substitute?

Posted: Wed Aug 20, 2008 8:46 am

I'm gonna go out on a limb here...

But my gut tells me you might be better off NOT using any of the products you've shown.

I know you're pretty well set on RC-2, but maybe moving to a 3rd layer of gypsum would be as cost effective?

Since your apartment is essentially two floors, I wonder if you might be able to reduce your flanking isolation at the wall/floor junction, in favor of straight forward floor coupling... at least you would have two floors below you to get disappated and one floor above.

As long as you can get the floor floating over the 703, I would think that would be one of the larger goals.

Prolly wrong, but my paultry .02 worth.

Posted: Wed Aug 20, 2008 10:42 am

Hehe, I do hope you're right about that. It sure would make this whole thing a lot simpler.

I forgot to mention in this thread that my contractor said we could use light weight steel for the wall studs instead of wood if it helps, and I remember Rod mentioning in the book that the light weight steel studs do perform better than wood. What if I placed a strip of 2" 703 under the walls just like the floor? Maybe 4" since the walls will carry the weight of the ceiling too? If that sounds doable, it'd be perfect because all my headaches will finally be gone. *Oh wait, I just remembered that light weight steel studs will not be able to carry the wight of the ceiling. Damn!)

Well, there's still the issue of how I would fix the new walls to the existing walls without those nifty ISO sway braces though. Did studio designers always had these sway braces with neoprene padding, or this is a new product? What did designers used to use before they invented these neoprene sway braces?

Posted: Thu Aug 21, 2008 9:46 am

Lunatique wrote:

I forgot to mention in this thread that my contractor said we could use light weight steel for the wall studs instead of wood if it helps, and I remember Rod mentioning in the book that the light weight steel studs do perform better than wood.

Ahh - that is only with single frame walls - with rooms within room the best is wood.

ALSO - lightweight studs will not carry the ceiling above.

Quote:

I just remembered that light weight steel studs will not be able to carry the wight of the ceiling. Damn!)

Good for you - you noticed without my mentioning it.

Quote:

Well, there's still the issue of how I would fix the new walls to the existing walls without those nifty ISO sway braces though. Did studio designers always had these sway braces with neoprene padding, or this is a new product? What did designers used to use before they invented these neoprene sway braces?

There are alternatives....... but making your own brackets is not one of them.

However - adding braces (1x4' would do just fine) in the walls running diagonal would do just fine as long as you add some to the ceiling as well (for the walls use 1x4's and slot the studs so you can just rest them in the slots.

For the ceilings use 2x4's that you cut to fit inside of the ceiling joist.

NOW - as far as your ceiling picture goes - yopu have it right - all you have to change is to lower the upper joist slightly so that you have clearance for the hangers above - and then you can hange what you need for the beams below directly off the upper ceiling -

Laying the joists on their sides would be a VERY bad idea - does the word "drumhead" bring anything to mind?

You want a stiff assembly.

I don't know why you can't find the braces in China - my good friend Norman Mason, of Mason Industries has sales in Hong Kong - here's the info:

Rep Name: Mason Industries Hong Kong Ltd
Contact Name: Rex Yiu
Address: Unit 1710, 17/F, Fortress Tower, No. 250 King's Rd. North Point Hong Kong
Telephone: 011-852-2967-9639
Fax: 011-852-2967-1772
E-Mail: mail@mason-hk.com
Website: www.mason-hk.com

If there is a problem - let me know and I will contact Norman directly - they are my most trusted isolation company - for a lot of reasons.

Rod

Posted: Fri Aug 22, 2008 6:47 am

Rod - I did contact Mason, and initially they were unwilling to sell to me because they prefer to handle the designing as well (as to not let unknowledgeable people use their product and ruin their reputation if things don't work out), and me being in the Fujian province made it unlikely for them to get involved. I asked if they could just sell their products to me and they said my project was too modest and I should try locally manufactured alternatives instead--that's when they gave me the link to that Chinese construction material website. I just contacted them again yesterday after having no luck with alternatives and begged them to sell their products to me, and it looks like they are willing, provided that I give them as much information/pictures/drawings/plans of my design as possible so they can figure out what I need from them. I'm going to be working on that for the next few days--to compile as much information as I can for them. I'm sick as a dog right now though, but I gotta work through this cold if I want to get the studio done. No rest for the wicked.

Now, some quesitons for you (and these are the only remaining outstanding issues left--or at least as far as I can tell). If you could address each of them, I just may be done with the research phase and can start ordering parts.

1) I would prefer to rest the ceiling's weight on the walls like you mentioned, but I think that's mutually exclusive from using hangers? If I rest the ceiling on the walls, there would be no need for hangers, right? Or am I getting this part wrong?

2) If I do rest the ceiling on the walls, just how would one do it with those annoying support beams on the ceiling dividing the whole thing into 4 quadrants? If I try to duck the joists below the beams totally, then I'd have no ceiling height left--I'd raise my hand and smack it on the ceiling. If I don't duck below the beams, I would need to secure the joists to the beams somehow, and wouldn't that create flanking problems?

(BTW, I realized I drew the ceiling diagram wrong. The blue colored joists should be turned 90 degrees to be along the width, not the length of the room.)

3) The 1x4' wall braces--I assume you mean they are placed between the joists? Or do you mean they hold the joists against the existing concrete wall? For the ceiling, I assume you meant to use the braces like the example in your book (page 77).

What I'm seeing in my head is probably completely wrong from what you're describing. I must ask you to forgive me, because I really have no experience with construction and what's common knowledge to you may be unknown to me. I'll do a little sketch to show you what I see in my head from reading your suggestion, and if I get it wrong, please correct me.

So, other than those questions, I think I'm pretty much all set--assuming everything goes well with Mason, that is. I really appreciate you offering to talk to them too. That's very nice of you. If I run into any more problems with them I'll be sure to call for help.

*Pictures Rod in shining armor on a white horse*

Very Happy

Posted: Fri Aug 22, 2008 9:11 am

Luna,

I will email you a couple of drawings I did for a studio I designed.

The plan A-1.4 is a plan view of the existing walls and 4x8 floor joist - the new walls inside the studio - and the new ceiling joists - note that the joists rest on the new walls and are carried by a center support (isolation hanger) to make up for the long span with 2x4 ceiling joists.

In the building sections you can see how I went about supposrting those joist - the only difference here being that your supports would be carried by the floor above - so you would use threaded anchors with threaded rod to carry the isolation hanger - and then the remaining detail to carry the joist would be the same.

You do this so that nothing touches the concrete beam - look at the detail entitled "example".

That also shows the method of dealing with the dropped concrete beam you need to deal with

This should clear things up for you.

Please send me your email address.

Thanks,

Rod

Posted: Fri Aug 22, 2008 9:31 am

Man, that's so awesome of you. I PM'd you my email address. BTW, you and your book were mentioned in my blog recently. Just helping to spread your name around. Wink

Posted: Sat Aug 23, 2008 8:51 am

It occured to me I never posted the floor plan of the room. It's the one that my contractor drew up in Autocad. I exported the section I needed into Photoshop and added the colored ink stuff:

Posted: Sat Aug 23, 2008 10:15 am

Lunatique wrote:

It occured to me I never posted the floor plan of the room. It's the one that my contractor drew up in Autocad. I exported the section I needed into Photoshop and added the colored ink stuff:

Rob,

I would recommend that you modify the left wall of your control room so that it was symmetrical with the right side (meaning the frames around the columns - this creates acoustic symmetry - which is desired in a control room.

An added advantage in doing this is that it creates more vertical corners that are excellent for bass traps.

Rod

Posted: Sat Aug 23, 2008 11:15 am

Rod Gervais wrote:

Rob,

I would recommend that you modify the left wall of your control room so that it was symmetrical with the right side (meaning the frames around the columns - this creates acoustic symmetry - which is desired in a control room.

An added advantage in doing this is that it creates more vertical corners that are excellent for bass traps.

Rod

Hmm, does that mean I'll have to sacrifice about a foot or more of my room's width?

I had read that when asymmetry happens behind your listening position, it's not as much of an issue. Also, I plan on putting as many broadband absorbers at every wall/wall, wall/ceiling/ wall/floor corners as the room will fit. Would that help? Also, that one beam that sticks out the most in the corner--it forms two mini corners. If I basstrap those two mini corners it's not as effective?

Posted: Sun Aug 24, 2008 12:06 am

OK, I redrew the walls so that there's now symmetry. I'd lose about half a foot in both width and length doing it.

I circled a question area with purple and drew an enlarged detail of how I'd try to not lose any more space (by placing the studs within the boundary of the corner beam. Is that ok?

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