Sway brace for inner wall top plate to truss connection?

Hi, I'm building a room within a room that is 22'x27' in Florida. It is an addition to my house and will share 2 walls with it. All of the walls will be 2 separate 2x4 studs, and the ceiling will hang from the roof trusses using clips and hat channel. Im trying to find a decoupling sway brace that I would use to connect the top plate of my inner wall to the bottom chord of the roof truss. The alternative is to use the WIC style braces that connect the inner and outer studs, but it seems that would give less isolation. However, it seems like they would be a lot easier to install. Does anyone have experience with these? Thanks!

I'm thinking that you would not want to use a brace attaching any part of your interior to the exterior...in Florida with hurricanes. You especially do not want to add any type of pull on the bottom side of a truss that changes the ability of the truss to deflect or yield with environmental conditions...like the winds from a hurricane. Have you considered OSB or MDF on the interior side of your interior framing to stabilize your walls?

I think that even with osb under the sheetrock, the 27' wall will be somewhat floppy without some sort of lateral support. In normal construction, the top plate would be connected to the truss directly wouldn't it? At the very least, the plates on the exterior walls are connected to the trusses using hurricane straps. So I dont think that using some kind of decoupling connection would be any different structurally. Im more worried about the loss of isolation from the bracing, so Im just trying to figure out the best way to do it. Ill attach a jpg of the plan in case it helps.

"I think that even with osb under the sheetrock, the 27' wall will be somewhat floppy without some sort of lateral support." It does require a ceiling that is framed to the new walls to be the most effective and to be a "room-in-a-room" type construction. "In normal construction, the top plate would be connected to the truss directly wouldn't it?" For load walls (typically the very ends of the truss) this would be correct. But for any other wall that may be inside the actual span of the truss (if it is NOT a load carrying wall) it would not make a direct hard connection but might usually be either cut short enough to allow for deflection of the truss or have some type of bracket to allow for this movement. "At the very least, the plates on the exterior walls are connected to the trusses using hurricane straps. So I dont think that using some kind of decoupling connection would be any different structurally." You are talking about two completely different pieces of hard ware that do two completely different things. The hurricane straps are used to >tie< the roof truss to the house in the event of damaging hurricane activity. That is why it is called a hurricane strap :) By design the straps make effort to keep the roof framing from flying off the structure, no matter from which side the wind is blowing. What you are wanting to do might be better installed if it is connected to the wall of your structure rather than the upper truss. But pictures prove a thousand opinions wrong everyday. In any event, I would get with the architect, designer or whoever is drawing your plans for verification of Dade County code if need be. Brien

"I think that even with osb under the sheetrock, the 27' wall will be somewhat floppy without some sort of lateral support." It does require a ceiling that is framed to the new walls to be the most effective and to be a "room-in-a-room" type construction.

But pictures prove a thousand opinions wrong everyday.

:wink: Since your design document calls for RSIC/Hatchannel at the ceiling, perhaps an alternative 27' interior wall connected to the exterior wall using one of these type assemblies would work as well? This is only one of many type decouplers available. I am curious about the "vaulted ceiling"(with DOUBLE layers of 5/8" drywall) and "truss" aspect of the your room design considering this is an addition to an existing structure. Can you elaborate or show a section or something. Are these new trusses, designed for this weight on the bottom chords...which I ASSUME are Scissor trusses since the plan calls for a vaulted ceiling. I'm also curious how the other walls are kept decoupled from the truss. Again, just curious.

Yes, the trusses are scissors and designed for the double sheetrock load. The sheetrock will hang from hat channel and clips on the trusses. The trusses will sit on the outer studwalls. The inner studwall will attach to either the truss or the outer wall via some kind of decoupling brace, but I don't know what yet. Does this all seem reasonable? Any obvious flaws? Thanks! Were pulling permits this week so nows the last chance to change anything.

I would like to point out that the clip/ hat channel ceiling doesn't offer as much isolation as an independent ceiling. A full room in room build would eliminate your floppy wall conundrum. Don't settle on a design because you want to pull permits this week!

I would like to point out that the clip/ hat channel ceiling doesn't offer as much isolation as an independent ceiling

Well, it all depends on the desired TL TARGET. You''d play hell trying to build an "independent ceiling" to match this wall. :mrgreen:

Yes, I know the clipped ceiling is a compromise, but the isolated ceiling was too much extra $$ and work and would have resulted in a smaller volume space. Now I can have a higher ceiling, which hopefully will improve the acoustics inside the room. But back to the sway brace: Can anyone recommend a product to connect the top of the inner stud wall to the joist, or should I use a WIC clip to connect the inner and outer stud walls? Thanks, Byra

cadesignr wrote:

I would like to point out that the clip/ hat channel ceiling doesn't offer as much isolation as an independent ceiling

Well, it all depends on the desired TL TARGET. You''d play hell trying to build an "independent ceiling" to match this wall.

External image, not preserved — original: http://httpics.com//is.php?i=1157&img=42036_leaf_wall_b.j.jpg

:mrgreen:

Great looking wall Fitz. Something you designed? ;)

I would tend to think this detail SHOULD have been on the plans when you submitted them to your local Building Inspection Department for approval. If they weren't, I would ask your BID about any codes which covers Truss connections at interior walls, as I'm sure there are some. I'm certainly no expert but I've read many articles on Truss uplift/wall connections, and it appears that this is a long term issue that has many concerns. Especially drywall joint cracking, if not outright wall lifting. Not to mention the structural issues of the trusses themselves. Personally, I would either consult with your GC or contact the truss manufacturer for thier reconmendations yourself. ESPECIALLY since the dead loading on the truss is more than normal(2 layers of drywall). From what I understand, Trusses can be engineered to connect at 2 or 3 points, and some manufacturers specify this by directly stamping on the truss. I would also tend to think your GC should be aware of this issue as it is probably code related in your area. In conclusion, I wouldn't decide on a solution based on forum advice. However, you may want to ask these guys.... http://www.inspectorsjournal.com/

Great looking wall Fitz. Something you designed?

Are you being facecious? :mrgreen: Sometimes I'm not sure. :? But to answer your question sincerely Brien, HARDLY. That picture came from a webpage for a Studio construction company in Europe. Frankly, I wish I had seen it 10 years ago. It might have saved me a ton of time I spent on TL research, but I just came across that picture a month ago...and actually, I posted that picture on that thread about 2 leaf vs 3 leaf walls...remember? Thats why I thought you MIGHT be being facecious, considering the content of that thread. :roll: :mrgreen: Concerning that wall though Brien, I'm STILL stepping on toes at other forums with this picture, and the BBC article. For some reason, people don't even want to discuss the implications and I STILL haven't got a REAL answer about the TWO LEAF thingy. :twisted: :roll: Even when I DIRECTLY ASKED....WHY IN THE HELL WOULD A PRO ACOUSTICS COMPANY SPECIFY AND BUILD WALLS LIKE THIS ...IF...A TWO LEAF SYTEM PERFORMS BETTER AND IS CHEAPER TO BUILD. Frankly, I think andre hit it on the nailhead...(sighs and rolls eyes :mrgreen: ) Brein, on a side note, this issue is only one of many I've come across in Studio Design over the years that finally came to a head on another forum called PRO REC WEB about 3 months ago. I won't go into detail on this thread, but something happened that proved to me there are certain people in the Pro Studio Design arena, that do NOT want certain facts known by the public at large, and certainly not "clients to be". In response to a series of questions I posed, the mods, who are Studio designers themselves, were forced to answer in "less than forthcoming" fashion(squirming is more like it), but although they seemed sincere, they were DEFINETLY not happy about it. They left the thread there.... for a month. A couple of weeks ago however, I returned to augment my thread with some more questions, only to discover not only couldn't I log in, I couldn't even see the Acoustics in Motion FORUM!!! 8O Over the next week, I contacted the webmaster numerous times as I would recieve a prompt saying i didn't have "permission to post". Finally, after numerous attempts to change my password failed, I began to suspect something wierd was going on. I finally asked the webmaster POINT BLANK...WHY couldn't he fix this problem. His last email explained it. Apparently, without notice, nor warning, nor by due process of RULES OF POSTING, the mods, whom I won't publicly name, had decided to COMPLETELY REMOVE ALL my threads, and without courage nor courtesey, didn't even have the balls to tell me I had not only been banned, but my questioning the Acoustic Powers that be should NOT be allowed to be seen by the public at large. Reminds me of the IRS. Apparently, when it comes to the use of SOME acoustic products, or public scrutiny of profesional ethics and opinins of products THEY use, or exposing acoustical dogma to the light of day makes some people uncomfortable...to the point they will remove any trace of scrutiny or alternate opinion from public view. UNF...INGBELIEVABLE. Anyway, my apology to the author of this thread for my rant. Carry on. :mrgreen:

I will check with the building inspector and also the truss company to see what is legal and recommended. I found this clip for connecting the inner wall top plate to the truss: http://www.soundproofingcompany.com/pro ... datasheet/ This seems like it would do the trick as long as the flex of the truss allows for its use. If the truss flex is indeed an issue, then I guess my only option is to use a WIC clip to connect the two stud walls together, which doesnt seem like a good idea for isolation.

cadesignr wrote:

Great looking wall Fitz. Something you designed?

Are you being facecious? :mrgreen: Sometimes I'm not sure. :? Anyway, my apology to the author of this thread for my rant. Carry on. :mrgreen:

Yes I was poking at you Fitz. To be fair, sometimes I am not certain what to expect from you...:) I think your input is valid in this thread and you should not need to request apology. Frankly the OP ( no damage intended) is asking to build something that does not need to be built. I don't know where in Gainsvile Florida he is...but I am 1 hour away from several Interstate points directly to Florida. And we build by the same code that comes from out of Miami..so there is no excuse for people in this business, in this five state area, not being aware of these kinds of issues.

Yes I was poking at you Fitz. To be fair, sometimes I am not certain what to expect from you...

Thanks for the honesty Brien. In fact, thats what you can expect from me..no more ...no less. Brien, I've NEVER claimed to be an expert at anything in relationship to this forum. But I see contridictions..and when I do..I'm gonna raise a flag so to speak. Again, thanks for being honest fitZ

Hi Xspace, What do you mean that Im asking to build something that doesnt need to be built? Do you mean that I dont need a connection from the inner wall top plate to the truss? Or something else? Please explain. We are on the verge of starting construction and I'm confused about this. Thanks!

What do you mean that Im asking to build something that doesnt need to be built? Do you mean that I dont need a connection from the inner wall top plate to the truss? Or something else?

That seems to be what Brien has been saying all along! And I tend to agree with him (mostly because he's the expert on construction, and I'm not). I'm still not convinced that you need that bracing, if the inner-leaf walls are built correctly.

That is why I started this thread in the first place, to see what you guys recommended. And I really appreciate the advice. So what keeps the inner wall from being 'floppy' if it isnt braced to something? Remember Im not hanging the ceiling from the inner wall, it will hang from the truss using clips. So that wont provide any structural support. And the walls are 27' and 16'. Thanks