# back blocking butt joints stronger?



## DAVE17352

I asked this question a few days ago along with a few others and I didn't get any opinions on this question. 

Do you think a back blocked butt joints (on ceilings) when split between trusses 24 inch on center is stronger and less likely crack bulge etc than breaking on the trusses themselves. I would be using 6" wide 1/2 OSB.

These would not be using butt boards but just flat OSB. 

Also would you hang the back blocking a few inches over on to the recess if you where to back block.

Thanks

Dave


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## moore

I think that would depend which two trusses your breaking between.
Factory trusses 2' on center are a joke as you know. If you use a flat backer board behind the butt between the wrong two trusses, you may end up with a real kitten to play with! 

When Factory trusses start walking..I really don't think it matters where the butts joints are...:whistling2: 

Back blocking between the trusses on the recess :thumbsup::thumbup:
You can't go wrong with that!!


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## Kiwiman

Yes....definitely yes, here we use scraps of drywall for backblocking and cove/cornice adhesive (powdered) for glue, you could use durabond also, avoid glue in a tube, it can be used but not ideal, the good guy's screw temporary shims over the seam to create a recess.
It's been done that way here for many years and we just don't get butt cracks that way.


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## DAVE17352

Kiwiman said:


> Yes....definitely yes, here we use scraps of drywall for backblocking and cove/cornice adhesive (powdered) for glue, you could use durabond also, avoid glue in a tube, it can be used but not ideal, the good guy's screw temporary shims over the seam to create a recess.
> It's been done that way here for many years and we just don't get butt cracks that way.



I plan to just put the osb behind the butt joint in between the trusses and then screw the osb in with a screws every 5 inches or so also a few screws a little wider. I have done one large ceiling like this and the joints look a lot flatter and stronger. My only concern is if they are actually stronger. I have no intention of using adhesive. Not because it wouldn't be as good, but just because the hassle. 

thanks for you info


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## PrecisionTaping

DAVE17352 said:


> I plan to just put the osb behind the butt joint in between the trusses and then screw the osb in with a screws every 5 inches or so also a few screws a little wider. I have done one large ceiling like this and the joints look a lot flatter and stronger. My only concern is if they are actually stronger. I have no intention of using adhesive. Not because it wouldn't be as good, but just because the hassle.
> 
> thanks for you info


How are they flatter? It's the same thing as landing on a truss if you're not using buttboard. I mean, there's still added strength, but there's nothing to make it flatter if it's just a regular piece of OSB...


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## moore

PrecisionTaping said:


> How are they flatter? It's the same thing as landing on a truss if you're not using buttboard. I mean, there's still added strength, but there's nothing to make it flatter if it's just a regular piece of OSB...


I was thinking the same thing!


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## PrecisionTaping

moore said:


> I was thinking the same thing!


lol ya. Weird.
If you're gonna do it that way and rip your own, at least buy some
Trim-Tex Shim on a roll and staple some on either side of your OSB piece.
This will force your sheets inward when you screw the middle and you're good to go.
http://www.trim-tex.com/product_catalog.php?cat_display=showproduct&id=92

Essentially creating your own buttboard.
Will work the same exact way.


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## DAVE17352

Gosh guys, I have hung board sense the late 70's. When you break on a stud or a truss if it is twisted, were the two ends meet on the surface it can easily be less flat than when you break on a 6 inch wide piece of OSB. I actually can't believe it is that hard for you fella's to figure it out. LOL.

But that being said. I tried the butt boards I had problems with them. But I still feel the backboards give me a better and Flatter joint. If the butt boards would have worked for me I would have used them. I also tried cardboard drywall shims on the sides they worked worse than the butt boards. 

:thumbup:


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## mudslingr

PrecisionTaping said:


> lol ya. Weird.
> If you're gonna do it that way and rip your own, at least buy some
> Trim-Tex Shim on a roll and staple some on either side of your OSB piece.
> This will force your sheets inward when you screw the middle and you're good to go.
> http://www.trim-tex.com/product_catalog.php?cat_display=showproduct&id=92
> 
> Essentially creating your own buttboard.
> Will work the same exact way.


Sounds like someone ran out of buttboard.:thumbsup:


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## DAVE17352

PrecisionTaping said:


> How are they flatter? It's the same thing as landing on a truss if you're not using buttboard. I mean, there's still added strength, but there's nothing to make it flatter if it's just a regular piece of OSB...


Fellas, flatter before taping. I also believe they will finish easier and closer to flat than if you break on the truss. Obviously not flat as if it was recessed with the butt board. Again the butt boards did not work for me. To many pulled through screws damaging the board. :thumbsup:


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## icerock drywall

PrecisionTaping said:


> lol ya. Weird.
> If you're gonna do it that way and rip your own, at least buy some
> Trim-Tex Shim on a roll and staple some on either side of your OSB piece.
> This will force your sheets inward when you screw the middle and you're good to go.
> http://www.trim-tex.com/product_catalog.php?cat_display=showproduct&id=92
> 
> Essentially creating your own buttboard.
> Will work the same exact way.


tt roll trim is to thick ...stores have drywall shims that work fine for this step. I make them all the time...just staple on the edge od the 6'' osb. and on the walls you don't even need the shims. it is flat between the studs


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## Kiwiman

DAVE17352 said:


> Fellas, flatter before taping. I also believe they will finish easier and closer to flat than if you break on the truss. Obviously not flat as if it was recessed with the butt board. Again the butt boards did not work for me. To many pulled through screws damaging the board. :thumbsup:


I know what you mean by being consistently flat with osb on the back, use fibafuse as well and see just how much flatter you'll get it :thumbsup:
The idea of using drywall instead of osb is the drywall and plaster type adhesive expands and contracts at the same rate as the board you are sticking it too, where as osb has potential for some differential warpage but probably not likely to crack I guess.
When using buttboards maybe use washers on your screws so they don't pull through, Moore sent us some so he'll know what I'm talking about.


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## PrecisionTaping

DAVE17352 said:


> Gosh guys, I have hung board sense the late 70's. When you break on a stud or a truss if it is twisted, were the two ends meet on the surface it can easily be less flat than when you break on a 6 inch wide piece of OSB. I actually can't believe it is that hard for you fella's to figure it out. LOL.
> 
> But that being said. I tried the butt boards I had problems with them. But I still feel the backboards give me a better and Flatter joint. If the butt boards would have worked for me I would have used them. I also tried cardboard drywall shims on the sides they worked worse than the butt boards.
> 
> :thumbup:


I still don't understand how you're having problems with the Buttboard?...
As far as I know, you're the only guy I've ever heard of who's had this problem.


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## DAVE17352

Kiwiman said:


> When using buttboards maybe use washers on your screws so they don't pull through, Moore sent us some so he'll know what I'm talking about.


Now drywall washers on the drywall screws thats new to me. 

It funny I have literally contracted over a thousand new homes for drywall. I have done most of my work in Nebraska but have also worked in Kansas, Colorado and in Northern California and besides typical scabbing in a board here and there, back blocking was not the norm in any of these places and certainly not in Nebraska. That's why I have all my questions about strength of the joint itself. Especially on the ceiling. But it sure looks stronger, flatter and better. 
:thumbsup:


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## DAVE17352

PrecisionTaping said:


> I still don't understand how you're having problems with the Buttboard?...
> As far as I know, you're the only guy I've ever heard of who's had this problem.


The screws pull through and like I said in the other thread the ultralite busts up much easier than regular 1/2 inch. I did think about using 54 butt boards on the lid and hanging them over the recess and screwing on the edges. Then a guy could dampen the joints and then screw down the butt. I bet that would work.


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## icerock drywall

DAVE17352 said:


> Fellas, flatter before taping. I also believe they will finish easier and closer to flat than if you break on the truss. Obviously not flat as if it was recessed with the butt board. Again the butt boards did not work for me. To many pulled through screws damaging the board. :thumbsup:


the first job my hanger used tt butt board on they pulled screws and damaged some rock...but they did get the hang of it. :thumbup:


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## keke

DAVE17352 said:


> I asked this question a few days ago along with a few others and I didn't get any opinions on this question.
> 
> Do you think a back blocked butt joints (on ceilings) when split between trusses 24 inch on center is stronger and less likely crack bulge etc than breaking on the trusses themselves. I would be using 6" wide 1/2 OSB.
> 
> These would not be using butt boards but just flat OSB.
> 
> Also would you hang the back blocking a few inches over on to the recess if you where to back block.
> 
> Thanks
> 
> Dave


I don't know what are the specs there but here it's a must


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## Mudslinger

Kiwiman said:


> Yes....definitely yes, here we use scraps of drywall for backblocking and cove/cornice adhesive (powdered) for glue, you could use durabond also, avoid glue in a tube, it can be used but not ideal, the good guy's screw temporary shims over the seam to create a recess.
> It's been done that way here for many years and we just don't get butt cracks that way.


I was just looking for info on this, thanks for posting it. I'm assuming you use laminating screws to hold the back blocking in place while drying, or is there another way you guys do it?


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## Kiwiman

Mudslinger said:


> I was just looking for info on this, thanks for posting it. I'm assuming you use laminating screws to hold the back blocking in place while drying, or is there another way you guys do it?


Normally a piece of metal ceiling batten (like in Keke's pic above)  screwed to the nearest fixing either side of the seam, and a shim under it (on the seam).
See page 46 here on this link will explain it better - http://gib.co.nz/assets/Uploads/Installation-to-Ceilings4.pdf


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## gazman

What we did with the steel battens as in Keke's pic, is we would kink them a bit with the drywall axe. So then when the drywall is screwed it formes a rebate much the same as a butt board. On most jobs we have ceiling access so we back block after it is hung.


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## Trim-Tex

Dave, Toe nailing (Screws) the butt edges (factory cut) to a possible crooked truss that is 24" on center is substantially weaker than a properly installed ButtBoard or back blocking system. Here are a few tips to help you succeed with ButtBoard and let you enjoy the recess that it provides. 1. Come to Chicago and get factory trained, thus you can practice on our $ to perfect your technique. 2. Use a 6' level and shim out the bad ups and downs and then start hanging. 3. When installing the BBoard , fully install it to the sheet that overhangs the joist/truss cavity with all screws 1" from end of board. 3. Now hang the next sheet BUT DO NOT put any screws in the closest joist/truss until after you put all the screws in the BBoard 1" from end. (Always start in the middle and work your way out) this is when the gypsum board is bending and screw mishaps will happen. 4. Last step is put in final screws into that nearest joist/truss that we avoided.

Good luck!
Joe


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## Trim-Tex

Dave17352

Do you want a box of 48" ButtBoard no charge so you can perfect your installation technique? If so PM me your UPS address and we will send out a box ASAP

Joe


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## MagicCityDrywall

Trim-Tex said:


> Dave17352
> 
> Do you want a box of 48" ButtBoard no charge so you can perfect your installation technique? If so PM me your UPS address and we will send out a box ASAP
> 
> Joe



Now that right there is unbeatable customer service name one other company ever that has EVER offered something like that, and consistantly


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## endo_alley

I have tried 8" strips of plywood, osb or whatever I can find. Even 6" steel track if that is all I have. I glue a shim lengthwise at each longitude edge so that there is a slight recess in the middle. I use spray contact cement for the shims. You can even put some spray contact cement at the actual (center of plywood) joint prior to hanging the sheet. Mostly for when we have level 5 finish. Seems pretty strong. And has the advantage of slightly recessing the butt joint. Doesn't work everywhere of course.


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## wannabeagoodmudder

I could not agree more with what Joe said!!! Way to set the bar high Trim Tex!


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## wannabeagoodmudder

Hey MagicCityDrywall, do you have any pictures of your drywall art? What do you use for tools? Do you use standard mud or something else?


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## bellas taper

If you install the taper on the sheetrock butt end before you hang it, would that work?


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## krem

we use 24mm metal batens, so when we do butt joints, we simply use some flooring board or pine decking board, its roughly 22mm thick, we put out butt joints in between 2 battens, make the board so it will span atleast 2 trusses where the join will be and so it covers the whole join, screw it to the trusses and then the butt joint to the board, it will give you a joint that will be pulled up by around 2mm, so when its trowled up, its nice and flat, its strong, builders usually have heaps of scraps of the board laying around so its free for us!!
krem


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