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Drywall Furring Channel Advice needed

post #1 of 50
Thread Starter 
Here is my dilemna. I purchased the furring channel yesterday and put the IB-1 sound clips up on the ceiling joists. However i miscalculated and the furring channel does not clear the 1" duct board that I used for the return air plenums for the living room upstairs. So the furring channel is not flush and flat. I suppse I could put some wood spacers between the clips and the ceiling joists to drop the clips so the channel can clear the duct board but I worry about head room with double drywall since My ceiling is very short to begin with. Need some expert advice here please.


post #2 of 50
YES, Headroom must be preserved. It shouldn't take long to redo the plenums. Add furring to the sides of the joists and recess the bottom duct board 1/2 inch. You should be able to reuse all those duct boards. Good DIYers aren't afraid to admit their mistakes and redo. So many times I see guys putting on band-aid solutions. You'll find that the time to redo something is much less than the time you spent originally.
post #3 of 50
Thread Starter 
The duct board is attached to the bottoms of the ceiling joists. When you say add furring the sides of the joists are you saying to put it on the inside of the joists for the plenums and put the duct board resting on the furring so that it's actually inside the joist cavity?
post #4 of 50
I just had to do this same fix myself and it didn't take long at all. I also beefed it up with a sheet of 5/8 drywall in the joist space. Any sound that makes it past my DD&GG clipped ceiling will meet another sheet of drywall before entering the return.

http://www.avsforum.com/t/1467977/media-room-and-bar-basement-build#post_23365917
post #5 of 50
Hmm, I have a similar problem; they ran the duct board on the bottom of the joists which doesn't really make sense. Seems like it would be quite a pain to relocate it higher up into the cavity. Thanks for the post, I'll look into that.
post #6 of 50
Quote:
Originally Posted by djkest View Post

Hmm, I have a similar problem; they ran the duct board on the bottom of the joists which doesn't really make sense. Seems like it would be quite a pain to relocate it higher up into the cavity. Thanks for the post, I'll look into that.

That's exactly why the HVAC contractor did it like that biggrin.gif

Tim
post #7 of 50
If you define PART of a Saturday to redo the duct a pain then it is a pain.

Remove the duct board
Attach 1x2s to the sides of the joists with the bottom edge one inch above the bottom of joists.
Lay the duct board on a piece of plywood,drywall or anything else you can use as a cutting surface. Trim to the width between joists with a straight edge and a utility knife.
Push up into the joist cavity and fasten
Tape/caulk making it air tight

Go have lunch.
Edited by BIGmouthinDC - 6/7/13 at 5:15am
post #8 of 50
Thread Starter 
I finally decided to add 3/4" wood blocking between the clip and the joist. The main reasoning was I did quite a bit of "customization" to the duct board to get it up there and it would of been at least twice the labor to take all that down instead of just taking the clips down. Now in a normal circumstance I would have brought the duct board up IN the joist but alas that was not my situation. However, it went fast and easy and all the clips and furring channel are up and looking good so i'm happy with the results. Thanks everyone.


However, was wondering instead of doing 2 layers of DW on the ceiling, Would it be better to put some fairly equivalent mdf board or something else to screw to the furring channel that way the bottom layer of drywall can get screwed in the wood instead of trying to hit the furring channel. Also the drywall seams will not meet on a furring channel as well which is why i'm asking this. So will I lose any soundproofing going MDF and DW instead of 2 layers of 5/8" drywall?

Thanks.
Edited by mijotter - 6/8/13 at 9:50pm
post #9 of 50
Thread Starter 
Anyone?
post #10 of 50
Theaters have been built with MDF and OSB first layers on the ceiling and walls without loss of soundproofing. They are usually done for reasons other than concern for seams not falling direct over the channels on the second layer. You should however not believe that you have a free pass and should attempt to screw into all the available channels on the second layer.
post #11 of 50
Thread Starter 
Oh yes I still intend to hit the furring with the second layer. Was just concerned about the seams not lining up on the channels. But that's good to hear about the MDF OR OSB for the first layer. What thickness would be comparable to 5/8" drywall?
post #12 of 50
Thread Starter 
Anyone know?
post #13 of 50
I've used 5/8 OSB
post #14 of 50

I'm just getting ready to put my channel up and my first layer is going to be 19/32" plywood.  My primary reasoning is that I have a fair amount of cosmetic "trim" that will go up after the walls and ceiling are enclosed and, as you mentioned, I wanted to be able to screw into any spot.  

 

Hope this all actually comes together as I have it envisioned in my head...

post #15 of 50
Thread Starter 
Yeah same here. Sounds like we're both at a very similar stage.
post #16 of 50
Thread Starter 
Jeff, that 5/8" OSB and Drywall won't be any less for soundproofing instead of 2 layers of Drywall?
post #17 of 50
Ask Ted White for the definitive answer.
post #18 of 50

I was told by Ted that there is a minimal performance penalty and that he specs out this type of arrangement all of the time.

post #19 of 50
Ted will say that it is all (OK, mostly) about mass and not so much the type of material. 5/8" OSB has a weight of 1.8 - 2.1 pounds per square foot (depending on manufacturer). 5/8" drywall is 2.31 psf and 3/4" MDF is 3.20 psf. So the clips and channel handle the decoupling, the Green Glue handles the damping and the sheet materials you use take care of the mass aspect of sound isolation. You can see there's not much difference between 5/8" OSB and 5/8" drywall. I understand your point about preserving as much ceiling height as possible, but I don't think another 5/8" to get the second layer of 5/8" drywall with Green Glue will make a difference.

Most folks who use OSB as their first layer do so because it gives a screw-worthy backer at ANY spot in the entire room for subsequent finishing steps, although it is advised to continue to reach your channel for additional support through the sheet material.
post #20 of 50
Thread Starter 
Thank you guys for your responses. However, it occurred to me(sooo many things on my mind) that 4x8 sheets of anything will no longer fit in my basement as the step wall is finished. Was wondering if there is a product to attach seams of drywall for my situation such as a backing or something. Would it be aweful if the first layer of seams don't hit a furring channel? The second layer will cover it up.
post #21 of 50
Thread Starter 
Anyone?
post #22 of 50
The beauty of a double layer 5/8 drywall assembly is that none of the edges have to hit a channel. Use the first layer as a backer for the final layer. I've done it many times.
post #23 of 50
I believe that BigMouthinDC has done that with out issue. The second layer, if hung in the opposite direction of the first, should stiffen everything up enough.

You could also do what my drywallers did. I tried to be extremely careful when putting up the stud walls to ensure that edges would land on a stud because I thought I may be doing it myself. What they did, was put up piece of drywall and cut it back to the last stud. Made for some wastage, but MAN did it go fast. In the end, they didn't care if the studs didn't line up perfectly to land on a seam; they made the seam fit the studs spacing.

[DANG!] Big got in there before I finished my post[/DANG!]
post #24 of 50
Thread Starter 
haha yep he's good. Thanks for the replies. My walls I did so that the seams would be on a stud but the furring channel I could not because of other constraints.
post #25 of 50
Thread Starter 
Any tips/advice from people who have done it before that I should know about before I install drywall on the ceiling with furring channels?
post #26 of 50
Push the drywall to the channel don't expect the screw to pull it tight. It is easy to strip channel with the screw if your over tighten and spin it a bit. It does require some getting used to if all you have ever done is drywall to wood.
post #27 of 50
Quote:
Originally Posted by mijotter View Post

Any tips/advice from people who have done it before that I should know about before I install drywall on the ceiling with furring channels?

Rent or purchase a drywall lift!!! Absolutely no substitute, I don't care how many friends you'd otherwise have helping you.

If you don't have a pro drywall screw gun with an automatic clutch, then there's a cheap alternative with a drywall screw "dimpler". Home Depot has a 5 pack of these things for cheap. Here is a fancier version: http://www.amazon.com/Bosch-D60498-Drywall-Dimpler-Phillips/dp/B0002EVG0W. It sets the screws perfectly and will help avoid some of the stripping issues BIG mentions.
post #28 of 50
Thread Starter 
Yep already have the dimple bit:) I did my best to square the room using 3 x 4 = 5 so we'll see how I did when the ceiling goes up.
post #29 of 50
I 100% agree on the drywall lift recommendation. Don't let anyone convince you otherwise. I finished a bonus room over the garage and was planning to rent a lift. Got talked out of it. Biggest mistake. Even though these strong guys were happy to help, you end up rushing to get the drywall screwed up before the arms give out. Went out and rented the lift so I could do the side panels that sloped down from the ceiling. Was soooo easy. Just lay it on, and crank it up, then leisurely put in the screws where they needed to go.
post #30 of 50
Drywall lift for sure. I rented one for $25 per day and it was totally worth it. With a lift you can do ceilings without anyone's help. The hardest part is lifting a full sheet onto the lift's rack. After that it's a breeze to tilt the rack and sheet horizontal and crank the wheel til the sheet's against the joists/channel. Then drive your screws leisurely, lower the lift and repeat.

If you have help, 1 measures and cuts while another cranks the lift up and screws. The 2 of you lift the sheet together onto the rack.

A lift is a must.
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