# Flattened Walls, Now a Drywall Bow: Install or Warp?



## rkearns10 (May 9, 2018)

I'm going crazy over here. I just spent a day flattening up my wall for tile, installed my sheetrock and now there's a bow in my sheet of drywall towards the end of a larger 8 foot piece butt joint. The differences is maybe an 1/8th to a 1/4" of split difference on each side of the bow so instead of floating hot mud into the sides of this, I'd prefer to fix it!! If you look closely in the picture I've attached below, I've marked the bowed area in pencil, it's just to the left of the right butt joint, directly preceding the joint. 

1) Is this my install method? IE am I employing the faulty succession of screw placements to create this?

2) How can I rectify this to remove this dang bow? 

3) Or could this be a warped piece of sheetrock? 

It's really frustrating spending so much time to true up the wall only to have another substrate hiccup, hopefully I can learn from this and/or fix it. Any help would be greatly appreciated, thanks so much!


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## mark sr (Jun 13, 2017)

Drywall will warp but usually regains it's shape once it's screwed to the studs. Are you sure there isn't some sort of trash behind the high side preventing it from laying flat?


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## Sdiver2489 (Jan 14, 2013)

I would just float it...no need to use hot mud on it unless that's your preference. Just float it out about 2 feet. One or maybe two coats of mud should do it and it'll be imperceptible. With how many screws are in that sheet I wouldn't want to take it down and try to put it back up.


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## rkearns10 (May 9, 2018)

Sdiver2489 said:


> I would just float it...no need to use hot mud on it unless that's your preference. Just float it out about 2 feet. One or maybe two coats of mud should do it and it'll be imperceptible. With how many screws are in that sheet I wouldn't want to take it down and try to put it back up.


Why no hot mud? I just ask because I was told to use hot mud on other walls to true them up for tile, by floating them flatter. - Also, the bow in this picture would be under tile and I was told to use hot mud vs lightweight all-purpose under thinset.

My concern isn't really the visbility of the hump, it's moreso getting that flat surface back before tiling. Maybe I'm a newb here but are 1/8-1/4" variances acceptable before thinset for tile? I suppose I could float here, but would that be the right move before tiling? The rest of the wall is pretty flat, it's just this one problem spot. :vs_mad:


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## mark sr (Jun 13, 2017)

Regular pre mixed j/c is easier to spread and sand. Setting compounds are not water soluble unlike regular j/c although moisture really shouldn't be an issue on a backsplash. I often use hot mud for the first coat and regular j/c for the final coat.


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## ClarenceBauer (Mar 4, 2005)

Under USG Joint Compound General Limitations item # 6 states " Use only Sheetrock Brand Setting Type for treating joints of Gypsum panels to be covered with ceramic or plastic tile".


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## Sdiver2489 (Jan 14, 2013)

People get backsplashes installed in their kitchen all the time...you think all of them have setting compound? Perhaps as a bare surface I can see why setting would be better...but if primed...shouldn't matter.


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## ClarenceBauer (Mar 4, 2005)

Sdiver2489 said:


> People get backsplashes installed in their kitchen all the time...you think all of them have setting compound? Perhaps as a bare surface I can see why setting would be better...but if primed...shouldn't matter.



I have NO IDEA what people use or why they use it. I was passing on specifications as written by one manufacture of joint compound material & the intended / designed use of that material. A home owner can use anything he likes & that meets his needs for any end results he desires. I read at one time years ago the follow " when everything else fails read these instructions " I still think that is good advice. Other printed instructions I have read on paper match books " Close Cover Before Striking " but they don't care whether you do or not it was just the manufacturers instructions.

If you are old enough to remember a Fram oil filter add in the 1950"s " you can pay me now for this FILTER or you can pay later for an ENGINE change "

I made very good money on the pay me later deal.


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## 195795 (May 24, 2013)

If you're prepping for tile, why not cement board ? I always do backsplash installs with CB


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## t.carpenter00 (Jan 23, 2018)

Setting compounds are harder. Better foundation for pretty much everything. 

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## t.carpenter00 (Jan 23, 2018)

BTW, you don't have enough screws in that sheet to make code. Get Clarence to tell you what they are. He has the book. 

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## ClarenceBauer (Mar 4, 2005)

t.carpenter00 said:


> BTW, you don't have enough screws in that sheet to make code. Get Clarence to tell you what they are. He has the book.
> 
> Sent from my VS988 using Tapatalk



https://www.usg.com/content/dam/USG...-gypsum-panels-installation-guide-en-J371.pdf
The above reference will give you the screw pattern 7 inches on perimeter & 16 inches in the field page # 13
Same info in the USG hand book Centennial Edition, Maximum Fastener Spacing page # 109

Note it states MAX. I like to do 8 inches in the field for Plaster work.


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## Sdiver2489 (Jan 14, 2013)

ClarenceBauer said:


> https://www.usg.com/content/dam/USG...-gypsum-panels-installation-guide-en-J371.pdf
> The above reference will give you the screw pattern 7 inches on perimeter & 16 inches in the field page # 13
> Same info in the USG hand book Centennial Edition, Maximum Fastener Spacing page # 109
> 
> Note it states MAX. I like to do 8 inches in the field for Plaster work.


According to your link its actually 12" for ceilings and 16" on edge for walls (since we are talking screw pattern).


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## ClarenceBauer (Mar 4, 2005)

Sdiver2489 said:


> According to your link its actually 12" for ceilings and 16" on edge for walls (since we are talking screw pattern).


Yes you are correct on the 16 inch spacing.


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## t.carpenter00 (Jan 23, 2018)

Just remember those as minimum. That's with paint as an overlay, not tile. 

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## NotYerUncleBob2 (Dec 29, 2017)

rkearns10 said:


> ...there's a bow in my sheet of drywall towards the end of a larger 8 foot piece butt joint. The differences is maybe an 1/8th to a 1/4"...


If you look at a sheet of drywall, the butt ends are the full thickness of the board and the long edges are tapered to account for the tape and mud so you can get a flat finish. Are you sure you're not meeting a butt end to a tapered side on that small piece? That'd be an 1/8th right there. 
It's also modern practice to not land butt joints on studs, but to use butt boards behind the joint in between the studs so you can create a taper that gets filled flat when you tape and mud. ...but that doesn't help you now. 
Take a long level and hold it to the wall. How flat is the rest of it?
Now, beyond the drywall issue...what's your trowel notch size for the thinset? I'm guessing it's a 1/4" or more so that will actually compensate for any imperfections less than 1/4" right there. No wall I've ever come across to tile has been perfectly flat. Some are pretty good, but sometimes you wind up like I did last week having to tile a backslash in an old house where I'd have been stoked to only find a 1/4" hump. Remember you're not joining airplane engine parts here, just tile. There's some wiggle room built in to the system.


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## ClarenceBauer (Mar 4, 2005)

NotYerUncleBob2 said:


> If you look at a sheet of drywall, the butt ends are the full thickness of the board and the long edges are tapered to account for the tape and mud so you can get a flat finish. Are you sure you're not meeting a butt end to a tapered side on that small piece? That'd be an 1/8th right there.
> It's also modern practice to not land butt joints on studs, but to use butt boards behind the joint in between the studs so you can create a taper that gets filled flat when you tape and mud. ...but that doesn't help you now.
> Take a long level and hold it to the wall. How flat is the rest of it?
> Now, beyond the drywall issue...what's your trowel notch size for the thinset? I'm guessing it's a 1/4" or more so that will actually compensate for any imperfections less than 1/4" right there. No wall I've ever come across to tile has been perfectly flat. Some are pretty good, but sometimes you wind up like I did last week having to tile a backslash in an old house where I'd have been stoked to only find a 1/4" hump. Remember you're not joining airplane engine parts here, just tile. There's some wiggle room built in to the system.


https://www.erieconstructioncouncil.com/plan_room_documents/General - Division 9(1).pdf#page=9
Check Div. # 9 Installation of Gypsum Panel System.
Look at Para. 3.04 - C NOTE " Center of Stud Flange "


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## NotYerUncleBob2 (Dec 29, 2017)

ClarenceBauer said:


> https://www.erieconstructioncouncil.com/plan_room_documents/General - Division 9(1).pdf#page=9
> Check Div. # 9 Installation of Gypsum Panel System.
> Look at Para. 3.04 - C NOTE " Center of Stud Flange "


See Section 12, Subsection 486, Paragraph 19, Ref 16j of table 12c diagram B, where it says: "_Pfffffffffffttttttt_!" 
I'm all for referencing and following codes and manufacturers directions, but using butt boards to avoid seam humps is a commonly accepted practice and is considered an upgrade to the old method of landing your butt joints on studs. When's the last time you hung drywall in a new home build? ...or even more than a patch at home? Not challenging your knowledge, just pointing out that things have been changing a bit in the last decade. Use of butt boards, drywall adhesive, new tapes and beads...it ain't you granpappy's plaster no more.
The only possible scenario where it might not fly would be if you're relying on your drywall panels to be the only shear bracing in which case you shouldn't be doing that anyway.


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## ClarenceBauer (Mar 4, 2005)

NotYerUncleBob2 said:


> See Section 12, Subsection 486, Paragraph 19, Ref 16j of table 12c diagram B, where it says: "_Pfffffffffffttttttt_!"
> I'm all for referencing and following codes and manufacturers directions, but using butt boards to avoid seam humps is a commonly accepted practice and is considered an upgrade to the old method of landing your butt joints on studs. When's the last time you hung drywall in a new home build? ...or even more than a patch at home? Not challenging your knowledge, just pointing out that things have been changing a bit in the last decade. Use of butt boards, drywall adhesive, new tapes and beads...it ain't you granpappy's plaster no more.
> The only possible scenario where it might not fly would be if you're relying on your drywall panels to be the only shear bracing in which case you shouldn't be doing that anyway.


Can you copy me a link to that Section 12 subsection 486.
Thanks


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## t.carpenter00 (Jan 23, 2018)

Actually, I had a rock hanger that jumped on that whole " let your butt joints land in space with backing" garbage. He tried that for 6 months. No one of us could talk any sense into him about that being a bad practice. But then we all started getting callbacks about cracking joints... I personally remember 1 house that had literally all the joints cracked inside of 6 months.
I understand why people think it's a good idea, but fundamentally, it's not.
Drywall is a structural member. It needs a foundation. In my 30 years of experience, you had best provide one.

And in 30 years of drywall, that one time period is literally the only time I have ever had to provide warranty work.
You couldn't pay me enough to break a piece of sheetrock off of the framing. I don't care how much work you think it saves. 

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## ClarenceBauer (Mar 4, 2005)

ClarenceBauer said:


> Can you copy me a link to that Section 12 subsection 486.
> Thanks


I should have responded to your question of when was the last time I hung Gypsum panels in a new home well that was about 2&1/2 years ago & the Gypsum board was USG Imperial Gypsum Base with Veneer plaster. I did not get to work on very many homes & the ones that I did get to install & finish Gypsum products on the last contract was in the range of $ 450,000. to around $850,000. & these homes were very large homes The home I worked on last was $ 16,000,000.00. I did very large commercial & Historical restoration & repairs & yes I did install Gypsum board most was for Veneer Plaster. It may not be my granpappy's plaster but I don't know of any drywall that has been installed & lasted as long as some of the plaster I have restored dating back to 1701. I did get to work on homes that had Gypsum boards installed around the late 1920's & 1930's and most had a plaster base applied. NO I DON'T DO DRYWALL installation or taping & finishing. Also all of the projects had specifications that had to be followed for all products to be installed as per manufactures written Specs.

I do have a question are the butt joint backer strips recommended by the Gypsum Manufactures Association?


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## NotYerUncleBob2 (Dec 29, 2017)

Ok Clarence, you win the pissing contest purely on the dollar value. But are you sure that last house wasn't $16,000,000.02? I'm sure someone added their two cents...
I'm not a fulltime hanger or finisher either, but I see what's been going on with the guys who do it and do it well. 
Unlike tcarp, I haven't heard much about call backs on any of the jobs I've seen go in with buttboards. Your one guy doing it must have screwed something up there. It's also not like I see it everywhere either, but when someone wants level5 on a long wall and there's a window that's going to throw raking light on it then the humps where the boards butt on studs are going to be a problem. Textured wall? Maybe not go to the trouble. Plastering over the drywall? Well yeah, then it doesn't matter as much there either I suppose.


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## t.carpenter00 (Jan 23, 2018)

No, it's just a matter of most guys not being willing to perfect the craft. I did level 5 for years. That's what I learned on. And in this age of poor finish and cover with texture... But it doesn't matter. 

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## ClarenceBauer (Mar 4, 2005)

NotYerUncleBob2 said:


> Ok Clarence, you win the pissing contest purely on the dollar value. But are you sure that last house wasn't $16,000,000.02? I'm sure someone added their two cents...
> I'm not a fulltime hanger or finisher either, but I see what's been going on with the guys who do it and do it well.
> Unlike tcarp, I haven't heard much about call backs on any of the jobs I've seen go in with butt
> boards. Your one guy doing it must have screwed something up there. It's also not like I see it everywhere either, but when someone wants level5 on a long wall and there's a window that's going to throw raking light on it then the humps where the boards butt on studs are going to be a problem. Textured wall? Maybe not go to the trouble. Plastering over the drywall? Well yeah, then it doesn't matter as much there either I suppose.


NO the House was $ 16 Mil. it was a new plantation house which was on 1,000 acers of land on the inland waterway. Not included as part of the house was an existing hunting Club house , Bunk house , an private aircraft runway. It was used in the past years by a very large hunting club. One of the Club members was the second largest Cement manufactures in the USA. It is located about 40 miles North of the Georgia / South Carolina State line. As for the two cents it was most likely a lot of cent's added. Just before I did this job I had just completed a Historical Plantation Restoration that was located on 16000 acers of land it was an old rice plantation.


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## ClarenceBauer (Mar 4, 2005)

I did find the plantation it is Jehossee Platation SC.
If you google it, It has a lot of info on it's history.
Also if you check the list in the upper right corner Plantations in SC I did plaster work on 10 of the ones listed maybe more kind of lost count.


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## t.carpenter00 (Jan 23, 2018)

I miss working on jobs that felt like it mattered... 

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## Domo (Nov 9, 2018)

If you trued the walls (plumb and square - or "flattened") then the rock should lay flat.

You have a bump behind the wallboard. Perhaps a mounting plate or nail plate for a wire/pipe penetration at the stud?

I always try to avoid butt joints on studs that have boxes because that's where you get bumps and all.

To me (a retired remodeling contractor and engineer) - sheetrock is inexpensive and 1/4" bump is LARGE. So, I'd simply pull the rock - double check the studs are plump with no bumps - remove and recess any nail plates that might cause a bow, mount the sheetrock to avoid any butt joint over a box location and move forward.

Then, I'd be able to sleep at night.

P.S. the suggestion about cement board as a backer was a good one...


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## t.carpenter00 (Jan 23, 2018)

You got to remember how rock is stored. It comes from the yard kinked and bowed. It gets banded, and set on bearing blocks. Look at it the next time you walk past a stack. It's seldom flat. Therefore, it's seldom straight. It's not as simple as saying " it's not flat, so something is done wrong". Especially nowadays, when drywall hits the skids when it's barely cooled off out of the dryers... 

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## Domo (Nov 9, 2018)

t.carpenter00 said:


> You got to remember how rock is stored. It comes from the yard kinked and bowed. It gets banded, and set on bearing blocks. Look at it the next time you walk past a stack. It's seldom flat. Therefore, it's seldom straight. It's not as simple as saying " it's not flat, so something is done wrong". Especially nowadays, when drywall hits the skids when it's barely cooled off out of the dryers...
> 
> Sent from my VS988 using Tapatalk


When I was working as a contractor I always rejected inferior/broken/bent/warped materials and have the vendor make a new trip to supply it. Only takes once or twice with a supplier and they learn.

I do agree that most materials are going downhill in quality.


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