Has anybody done this yet?

Given that the flange at the bottom of the joist isn't tall/wide enough to accommodate the vertical portion of the EXT-04 clip, I need to arrange some blocking.

Bpape suggest some 1"x3" on either side of the joist laminating it between them to provide blocking/surface to attach the EXT-04.

Has anybody done RSIC clips on manufactured i-joists?

This is for partition walls?

No. I'm using DC-04 on the partition walls.

I'm looking at the EXT-04 for the ceiling in order to maximize ceiling height.

I know Strange Brew and Cathan used a blocking system to get the RSIC-1 up into the joists, but the EXT-04 seems to be tailor made for this application. Do you have a different suggestion?

There are some pics in this post of attaching blocking to the sides of joists and using RSIC and channel in a minimal head loss configuration. For engineered joists it would probably be a good idea to use a sandwich or at least big washers because the OSB portion of the engineered joist isn't as stable as a regular solid wood joist.

http://www.avsforum.com/avs-vb/showthread.php?p=15180364#post15180364

http://i464.photobucket.com/albums/rr6/ikelman/2008_0721hometheater0082.jpg

And aren't ther knockouts in the OSB portion? You wouldn't want to attach something to a knockout without realizing it and then have it just fall out. The sandwich sounds like the best idea to me.

There are some pics in this post of attaching blocking to the sides of joists and using RSIC and channel in a minimal head loss configuration. For engineered joists it would probably be a good idea to use a sandwich or at least big washers because the OSB portion of the engineered joist isn't as stable as a regular solid wood joist.

http://www.avsforum.com/avs-vb/showthread.php?p=15180364#post15180364

http://i464.photobucket.com/albums/rr6/ikelman/2008_0721hometheater0082.jpg

Had I to do it all over again, I would have used those style of clips. The blocking would have been easier to install. I don't think they were available at the time that I did mine. Oh well.

http://www.soundproofingcompany.com/media/rsic-dc04/rsic-dc04_datasheet.pdf

You can do the blocking as Big showed there. Given that you are not sustaining a vertical force, but rather a mild lateral force, I personally don't think the blocking is necessary.

BTW, In case we have people who are scrutinizing pictures, etc, you wouldn't want to install clips and channel over MLV as shown in the pics. The resulting small trapped air cavity will compromise performance.

I mean absolutely no disrespect to whomever's theater that is.

http://www.soundproofingcompany.com/media/rsic-dc04/rsic-dc04_datasheet.pdf

You can do the blocking as Big showed there. Given that you are not sustaining a vertical force, but rather a mild lateral force, I personally don't think the blocking is necessary.

Only reason I had to do block for mine is otherwise the clip won't clear the joist. I imagine it's the same with the installation shown in the above picture. The edges that hook around the hat track would tough the joist.

I mean absolutely no disrespect to whomever's theater that is.

The author of that thread admits it was an error.

There are some pics in this post of attaching blocking to the sides of joists and using RSIC and channel in a minimal head loss configuration. For engineered joists it would probably be a good idea to use a sandwich or at least big washers because the OSB portion of the engineered joist isn't as stable as a regular solid wood joist.

http://www.avsforum.com/avs-vb/showthread.php?p=15180364#post15180364

http://i464.photobucket.com/albums/rr6/ikelman/2008_0721hometheater0082.jpg

This is the closest I've seen to what I think I want to do.

I would have to rest my blocking on top of the flange, however. And I would certainly put more blocking behind and use a screw to laminate both side. Alternatively, we were talking about running lengths of 1x3 all the way down the joist on top of the flange.

Here's what I had in mind (I'm using a piece of MDF here, obviously it would be a cut down 1x4 or 2x4 instead.

http://i357.photobucket.com/albums/oo20/TheRanchHT/IMG_0027.jpg

If I understand the products you are going to use I think you need something thicker to clear the lip of the joist. I think I would try pieces of a 2x6 on the side with the RSIC.

I think you're right.

The "lip" or ledge formed by the flange portion of the i-joist is ~1" wide.

So standard 2x6 material would only overhang the flange by .5". I don't know if this is enough clearance for the clip.

Ok, I may revamp what I've been considering:

If I span the joists with a 2x4, with the 2x4 resting on top of the flange itself, then I could use RSIC-1 or even RSIC-V in a more 'traditional' installation.

If I used RSIC-V, I could cut costs and perhaps retain more ceiling height, as it appears that the V has reduced overall installation depth.

Third post in a row. Aren't I eager?

Here's what I'm describing (with a chunk of drywall as a mockup).

The joist flange is almost exactly 1.5" tall, so give that a RSIC-1 with hat is ~1 5/8" deep, it should hang only 1/8" lower than the joists. It's tight, but it might be perfect.

http://i357.photobucket.com/albums/oo20/TheRanchHT/IMG_0029.jpg

http://i357.photobucket.com/albums/oo20/TheRanchHT/IMG_0028.jpg

1/8" may be too tight. If there is any variation between the joists you may end up with a coupled ceiling. I gave myself about 1/2" clearance just to be on the safe side.

I think some washers on the RSIC-1, or even a thin wood shim would work. I'm also counting on the fact that the manufactured joists might have less variation.

I think some washers on the RSIC-1, or even a thin wood shim would work. I'm also counting on the fact that the manufactured joists might have less variation.

Washers would work. Shims can crack and split.

http://www.pac-intl.com/pics/rollover/rsic1.gif

Looking at the design of the clip you can see that to work properly you would need a pretty big washer. It should totally cover the upper rubber legs. If it slips inside the legs it will decouple the clip.

I think I would cut some 3x3 squares of a dense 3/8 plywood.

http://www.pac-intl.com/pics/rollover/rsic1.gif

Looking at the design of the clip you can see that to work properly you would need a pretty big washer. It should totally cover the upper rubber legs. If it slips inside the legs it will decouple the clip.

I think I would cut some 3x3 squares of a dense 3/8 plywood.

I think this is the best way to go.

I'll take some pictures as I go along. I would be lost without some of the pictures and comments Cathan and BMiDC have put up over time here.

OK, next question. What is your plan for securing the cross pieces?

If it is screwing through the OSB part and into the ends. Not too hard. But if it is screwing through the flange you are in for a surprise. Those things are dense and hard to put a big screw through. I had to drill pilot holes to secure blocking for my walls that ran parallel to the joists.

Also if you want to screw from the top side down into the flange you've go a very awkward angle.

I would do one as an experiment to be sure you really want to commit to the cross brace technique.

One last argument for the original approach. With the side block approach you have a lot of flexibility to adjust the clip up and down to compensate for a sagging joist (if any).

With the cross braces you would need to adjust the thicknesses of the shims which would be more time consuming.

Well, most of the weight will be supported by the downward force on the flange itself. So securing the cross braces shouldn't require a ton.

My first thought was firing an air nail through the flange and into the brace at an angle. Basically toe nail them in. I might only need a nail or two to secure it down.

Otherwise a nail through the OSB and into the end of the brace would work.

Try one you might be surprised how dense the flange is. You also need to be aware that this design may be prone to squeaks.

Try one you might be surprised how dense the flange is. You also need to be aware that this design may be prone to squeaks.

I hadn't thought of the squeak aspect, actually. Although, I will be resting the blocking on the flange, regardless of the orientation of the blocking and the clip. Maybe I need to lay a bead of something on there.

I think the flanges look like they are dipped/soaked in glue or soemthing similar. Is this what creates the additional density?

Will the down force on the flanges support two layers of dry wall?

Hey Irv. Yes they will. If you stick with the 24" row spacing and clips spaced no more than 48" along a row, it will support double 5/8" just fine.

Ted -

I'm getting ready to lay out my ceiling grid parallel t othe joists and want to confirm....

Rows 2 feet apart, clips every 4 feet and then it doesn't matter which way the drywall runs over the grid. So for a single 4x8 sheet, that would be nine clips. Correct?

The theater area of my room actually has joists 12" OC so that's easy enough...every other joist. Then it opens to a little higher ceiling at 16" OC. Does that mean I need to run clips along EVERY joist? Would that change the spacing along the row? Again, just want to confirm.

Thanks,
Tom

Hey Tom,

That's the deal. Rows are 24" apart. Each row has clips spaced no more than 48" apart.

Best to start all ceiling clips at 1 wall. Measure out 4" or so and throw a row there. Then 24" FROM THE WALL, measure out and throw your second row. So the second row is not 24" from the first row, it's 24" from the wall. Third, fourth, etc rows are all 24", 48", etc from that second row and so on.

This way, you throw up the first layer of drywall perpendicular to the rows of channel and the ends hit channel every time.

Make sense?

Will the down force on the flanges support two layers of dry wall?

The specs for my model of joists indicate much more aggressive arrangements. They are capable of supporting a fireguard style wall. Three layers of 5/8 on hangers.

Whether the force from the clips is coming from a point contact below the joist or from a block on top shouldn't make a difference, I don't suspect. In fact, you are spreading that clip over two joists now.

I'm not an engineer, but I did stay in a Holiday Inn Express last night.

Geez, I misunderstood Irv. I thought he was asking about the clip, but he was asking about that bottom flange.

They are rated for large ceiling loads as you say. Double 5/8" is a minimum, as that is the standard for a 2 hour rated system.

I'm not sure if there is a common spec minimum that they all need to meet, but double 5/8" is an extremely common construction.

Hey Tom,

That's the deal. Rows are 24" apart. Each row has clips spaced no more than 48" apart.

Best to start all ceiling clips at 1 wall. Measure out 4" or so and throw a row there. Then 24" FROM THE WALL, measure out and throw your second row. So the second row is not 24" from the first row, it's 24" from the wall. Third, fourth, etc rows are all 24", 48", etc from that second row and so on.

This way, you throw up the first layer of drywall perpendicular to the rows of channel and the ends hit channel every time.

Make sense?

I'm actually completely confused now. But I know there are a ton of diagrams describing clip/ hat track arrangements, so I might go hunting for one.

http://www.soundproofingcompany.com/media/whisperclip/whisperclip-instructions.pdf

See page three of this puppy. It's a wall diagram, but same schematic for a ceiling. From the floor you come up 3-4" and put a horizontal row of Hat Track. That's row #1.

For row #2 you measure again from the floor up 24" and that's the center of row #2. Then 24" from row 2 is where row #3 goes.

The point is that to establish placement of row #2 you measure 24" from the floor, not 24" from row #1

Think I got it. Diagram helps.

Thanks!

Groovy. Call with any questions if you'd like 800-397-8791

My joists are actually 19.5" on center.

So I can't go every third joist (58" between clips).

If I go every second joist, that gives me 39" between clips. Is there any reason to NOT do this (other than cost)?

Actually there is a reason. You want the flex and resilience from the 48" spacing. Less won't kill you but 48" is better

Ted,

What is your recommendation when you have people with odd joist spacing? Just create blocking?

Well, generally clips and channel are installed with either 16" or 24" OC joists. Sometimes 12". 19.5" is odd.

I would use the blocking to optimize the clip spacing. Then run the clips / channel rows parallel to the existing joists if possible. This will allow you to maximise finished ceiling height by having some of the clip assembly up in between the joists. And then I would recommend standard 2-piece clips, not the more expensive Ext clips. Save the $.

Ted,

How do you finish the corners? You say:

Caulk around the perimeter of the wall. Use fire and
smoke rated acoustical sealant where required.
Mud and tape the seams and corners as per standard drywall finishing.

Does this mean you have to caulk the corner, wait for it to dry, then mud and tape the corner? Or can you caulk and then beging to mud and tape?

Also, how "good" (eg, smooth) does the underlying drywall layer's taping have to be?

Thanks.

You don't tape or mud the first layer. And for that matter if you are covering the walls with fabric, you don't need to do much tape-mudding on the second layer either.

You don't tape or mud the first layer. And for that matter if you are covering the walls with fabric, you don't need to do much tape-mudding on the second layer either.


Exactly right. The key is to watch for obvious gaps in the first and second layers. Fill those before proceeding. Try and keep the drywall joints tight.

If you are mudding and taping the second layer, you can caulk and proceed to mud and tape right away.

You don't tape or mud the first layer. And for that matter if you are covering the walls with fabric, you don't need to do much tape-mudding on the second layer either.

That just saving me a crap load of time! Thanks. I can't tell you how much easier this makes my project.

Hey, my Fine Home Building magazine had a short article about a corner piece for drywall used instead of tape. It has a paintable rubber section in the corner. The section is supposed to help with cracking, for walls that move a lot over the seasons. However, I was thinking that it might also be good for these types of walls, as it would allow some movement between the walls. I'll post the link to it this weekend, and then you can give me your thoughts.

You don't tape or mud the first layer. And for that matter if you are covering the walls with fabric, you don't need to do much tape-mudding on the second layer either.

Depends on when you are planning your final inspection. If it is before you put up your fabric walls the walls need to be taped and mudded. They don't have to look pretty but they have to be sealed.

If your final is after treatments then he can't see what he can't see.

Here's the link to this flexible center joint:

See the Magic Corner Expansion Bead (http://www.trim-tex.com/cornerbead.htm)

This looks interesting, although the smallest section is 100 feet. That's not bad if you're doing the ceiling and walls and wouldn't be enough for my room, so I'd have to get the 250 feet section. I'm also not sure of what the price is, but considering GG and RSIC make up a thousand plus dollars, the cost may be incremental.

Bob, That is an interesting piece of goods. But we should know that we want mass everywhere. CRacks covered with that little rubber middle won't help us, but will give the illusion of a seal.

Better to stick to the sealant if there are cracks.

Well, generally clips and channel are installed with either 16" or 24" OC joists. Sometimes 12". 19.5" is odd.

I would use the blocking to optimize the clip spacing. Then run the clips / channel rows parallel to the existing joists if possible. This will allow you to maximise finished ceiling height by having some of the clip assembly up in between the joists. And then I would recommend standard 2-piece clips, not the more expensive Ext clips. Save the $.

Ted:

Care to ballpark what my loss of performance might be if I went the simple route and put the clips on every second joist (reducing the inter-clip distance to 39")?

Hmmm... This is a tough question. The performance reduction would be minimized with the use of more mass, insulation and damping. For example using a third sheet of drywall would make up some of that loss.

But let's assume you do not add a third sheet. You have a stiffer ceiling structure (from an isolation perspective). Biggest area affected would be the low frequencies, and this is the isolation we're after. You'll be raising the resonance point of the ceiling. So whereas before you would have good isolation down to 60Hz, now you would be good down to maybe 80Hz. These are just examples, obviously. Your structure would be unique.

So you see the answer to your question is frequency dependent. You might have a "5%" loss at 125 Hz, and a "50% " loss at 70Hz

I would really, really encourage you to buy fewer clips and consider some blocking.

Ted -

So, to run parallel at 16" OC, every third joist would give you the 48" and then you would run the 24" spacing along each row? Which way would the drywall run?

I pinged PAC-Intl last week for a drawing but haven't gotten a response yet.

Thanks for the help! You've been great here.

http://www.soundproofingcompany.com/media/whisperclip/whisperclip-instructions.pdf

Generally track runs perpendicular to the joists. New rows every 24". So an 8' wall would have a starter track in the bottom, then every 24" horizontal. So another 4 rows of track going up the wall like a ladder.

Along each row of track, clips are spaced every 48". Every thirs joist or stud when dealing with 16" original framing spacing.

Right, but to minimize loss of height I need to run parallel. So do you just recommend blocking to get that 24" spacing as you describe?

Ah! Yes to max your height, running clips parallel to joists is great. You'll need blocking to accomplish. If you have joists that are free of a lot of mechanicals and you can do this, great.

Mechanicals are along one side of room inside soffit, so fortunately, I have the room to work, it's just more work than I had anticipated. But isn't that the way it ALWAYS is?

Thanks,
Tom

LOL. Yes, It is always

For row #2 you measure again from the floor up 24" and that's the center of row #2. Then 24" from row 2 is where row #3 goes.

The point is that to establish placement of row #2 you measure 24" from the floor, not 24" from row #1

Ted,

I'm at the point where I'm putting up my clips/track. I remember reading your comments above.

None of the diagrams showing clip layout clarify where row #2 should be.

I'm confused as to the purpose of putting row#2 twenty-four inches from the wall instead of 24" from the first row.

That would mean there is a ~18" - 20" gap betwen row #1 and row#2.

Here's my plan for my current clip layout. Please feel free to comment, as you see fit. I started on the RIGHT in my measurements, not the left. The layout here has the first row of hat channel/clips ~3.5" from the right wall, then the NEXT row is 24" or ~20.5" to the left of row #1.

http://i357.photobucket.com/albums/oo20/TheRanchHT/RSICplan.jpg

The requirement to have row #2 24" from the wall (not 24" from row # 1) is so that you can start your 48" wide x 96" drywall at the wall and be assured to have a hat track to support the edge. The 24" spacing therefore needs to start from the wall edge.

If you complete the dimensions along the X-axis, you will see that a 24" multiple panel (4x8 drywall) will not have an edge to secure to

Ok, this is what confuses me:

Doesn't row #1 being 3" from the wall ensure that the edge will always be supported?

Ok, this is what confuses me:

Doesn't row #1 being 3" from the wall ensure that the edge will always be supported?

Yes, but what about the other edge?

The requirement to have row #2 24" from the wall (not 24" from row # 1) is so that you can start your 48" wide x 96" drywall at the wall and be assured to have a hat track to support the edge. The 24" spacing therefore needs to start from the wall edge.

If you complete the dimensions along the X-axis, you will see that a 24" multiple panel (4x8 drywall) will not have an edge to secure to

Ted, I think that is how he has it. The first row is 3.5" form the wall, the second is 20.5 from Row 1 so that makes it 24" from the wall. He then has 24" spacing until he reaches the other wall.

Does he? Hell.. he does. I see that now. oops.

Well that would be fine then.

Does he? Hell.. he does. I see that now. oops.

Well that would be fine then.

It is how I have it...but that's strictly because you said so.

I'm terrible for needing to know the "why" in addition to knowing the "how"!

It is how I have it...but that's strictly because you said so.

I'm terrible for needing to know the "why" in addition to knowing the "how"!
Nothing wrong with that!

Do you understand "why" now? If not, you will when you install the drywall! ;)

We're re-working our diagrams today, actually. Our presentation can be clearer and simpler.

I get it now...and it's a great example of over-focus. Worry too much about one end and you forget about the other!

Great. The questions are welcomed.