# How to fix these corners?



## DeanV (Apr 18, 2007)

The corners in these pictures close completely in the summer but look like this in colder weather. The cracks run the entire length of the wall along the cathedral ceiling, about 24'. I have seen similar cracks in other home as well that do this, some open 3/8" seasonally.

Is there a fix for this? What is the cause? It is much more than the typical hairline seasonal crack.


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## straight_lines (Oct 17, 2007)

High quality caulk.


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## Capt-sheetrock (Feb 10, 2008)

This a problem called "truss up-lift" . Some engeniers have decided that the rafters should NOT be permantely attached to the walls. This technique will cause the rafters to lift off the walls seasonally(cathedrals are worse cause there is no ceiling joist, just rafters). Drywallers argue back and forth on this subject, just about like painters argue about 18's VS 9's. If you want to know more than you want to know about truss-lift, just search it on any drywall forum.

The answer as to "fix it", there is none. As long as the rafters can lift, they will. You could put crown up and only nail it to one side (ceiling or wall) and let the crack do its thing behind the crown. But you can never fix moveing framing members with paint and/or caulk.


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## 2buckcanuck (Dec 14, 2010)

truss lift is worse in the 1st year that a house was built,it gets less and less worse over time,it lifts less.you could try reversing the screws or driving the nails all the way through on the ceiling sheets.that way there is a bit less lift.this will require re-taping though,and not a guaranteed fixed
here's a link on truss lift http://www.renovation-headquarters.com/roof-truss-uplift.htm


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## 2buckcanuck (Dec 14, 2010)

sorry,I mean back off the screws where the ceiling sheets touch the walls,so the walls carry the ceiling ,and then that area of the rock is not attached to the joist


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## DeanV (Apr 18, 2007)

I heard that term before, but it was in conjunction with a regular ceiling. I did not connect the dots and realize it applied to this style ceiling as well. Thank you for the info. If I recall, there is a certain kind of track you drywallers can install where the ceiling and wall meet that minimizes this, if of course the GC is willing to pay for it.


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## Capt-sheetrock (Feb 10, 2008)

2buckcanuck said:


> sorry,I mean back off the screws where the ceiling sheets touch the walls,so the walls carry the ceiling ,and then that area of the rock is not attached to the joist


 Ya got to remember that 2buck is from Canada and he don't speak english too good.

What he is trying to say (in english) is remove all and any fastners from the lid where it meets the wall, so that the last rafter can move up and down at will and the lid board will sit (with its own wieght) on the wall board.:thumbsup:


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## Capt-sheetrock (Feb 10, 2008)

DeanV said:


> I heard that term before, but it was in conjunction with a regular ceiling. I did not connect the dots and realize it applied to this style ceiling as well. Thank you for the info. If I recall, there is a certain kind of track you drywallers can install where the ceiling and wall meet that minimizes this, if of course the GC is willing to pay for it.


 Yes thats true, but it doesn't work very well either. When the framing moves it takes everything with it. The best way is like 2buck mentioned, not to screw or nail the lid board around the edge. The problem is that nobody every mentions wheter the trusses are attached or floated. 

There really is no good answer to this problem (that I know of). I do agree that it is a major problem tho.


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## DeanV (Apr 18, 2007)

Well, if it helps mend any rifts between drywallers and painters, I have not blamed drywallers for this problem.


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## Capt-sheetrock (Feb 10, 2008)

DeanV said:


> Well, if it helps mend any rifts between drywallers and painters, I have not blamed drywallers for this problem.


 Yeah, we like to poke at eachother,, just kinda goes with the territory. This is one of theose circumstances that suck, no real good answer and no real way to fix the problem. Its hard to tell someone, "your house has this problem and there is no way to fix it"


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## 2buckcanuck (Dec 14, 2010)

DeanV said:


> Well, if it helps mend any rifts between drywallers and painters, I have not blamed drywallers for this problem.


there's rifts between drywallers and tapers
truss lift tends to happen more in colder climates,and does not happen near exterior walls,it happens more on walls that are more to the middle of the house,a hallway would be a good example.they use to put up 1 x 2 steel backer and nail it to the wall,the steel would hold the ceiling sheet in place and prevented it from lifting up with the trusses.you did not screw into the steel on the ceiling,in case you caught a truss.then guys began to figure out to not put screws in the edge of the ceiling sheets,let the wall sheets carry the load,and your 1st screw in the field stayed back a good 16 inches from the wall in your ceiling sheet.this helps minimum the lift,and stops it in many cases,but not all the time,alot depends on the length of the trusses .the longer the trusses,the more potential for lift.thats why i was saying in my last post to try and back out the screws/nails in the perimeter ,so the ceiling sheets rest on the walls.
so now you know who to blame,the trusses,builders or rockers combined (sometimes)not your taping buddies:yes:

in your case,back those nails/screws out,let it sit for a few days,let gravity do it's thing on those ceiling sheets.then tape it in,thats all you can do,if it's a older house,they may not lift again,but you can't grantee it though.
need taping advice


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## DeanV (Apr 18, 2007)

Those pictures were from the in-laws home and that joint has always bothered me. Since the ceiling is stomped, I do not think I want to go through the hassle it would be to try to fix it.

If I do though, fiberglass mesh tape or paper?


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## 2buckcanuck (Dec 14, 2010)

DeanV said:


> Those pictures were from the in-laws home and that joint has always bothered me. Since the ceiling is stomped, I do not think I want to go through the hassle it would be to try to fix it.
> 
> If I do though, fiberglass mesh tape or paper?


you just made the captain spit his beer on his pc screen using that "M" word.use the stuff the pro's use:yes:


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## Capt-sheetrock (Feb 10, 2008)

DeanV said:


> Those pictures were from the in-laws home and that joint has always bothered me. Since the ceiling is stomped, I do not think I want to go through the hassle it would be to try to fix it.
> 
> If I do though, fiberglass mesh tape or paper?


 Paper,,, never mesh,for anything,period.

I'd use level-line, its a no-coat product. It is paper, but its a bit tougher.

BTW no-coat is the brand name, you still have to coat it,,,, if you don't the painter's gonna hate you,,,lol.

What is involved here is this. You have to un-fasten the rock ceiling at the wall, tape, finish and then re-stomp the lid (you can problly match the stomp up so you won't have to re-stomp the whole thing) then re-paint the wall.


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## Metro M & L (Jul 21, 2009)

Ok capt,

what about the big 36" mesh used for stabilizing old lathe and plaster? I just did six rooms, three coats. Should I have used paper?


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## 2buckcanuck (Dec 14, 2010)

not that I'm the capt
what did you coat that mesh with.hotmud,or straight mud ??


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## Paint and Hammer (Feb 26, 2008)

2buckcanuck said:


> not that I'm the capt
> what did you coat that mesh with.hotmud,or straight mud ??


What's the difference other than time? (serious question)


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## 2buckcanuck (Dec 14, 2010)

if your going to use that Mesh stuff,it has to be used in conjunction with a hot mud to give it strength,using regular mud will crack a few months down the road on drywall,
but to help you guys check out this product,it's getting good feed back on drywall talk.it's called fibafuse http://www.sgtf.com/Brands/FibaFuse
will explain best way to fix plaster later,it's bed time,or the capt will tell you


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## 2buckcanuck (Dec 14, 2010)

I'm back
you guys got me to thinking,your normally repairing over walls that have been painted,so the rules will change for you when using mesh or paper.here's trying to explain without starting a mesh vs tape war on this site.
mesh tape has a adhesive on one side that ad-hears to the drywall and must have a hotmud applied to give it added strength.
paper tape in conjunction with a proper taping mud acts as a bonding agent,not just as a adhesive,there is a chemical reaction between the two.to me,if it was metal work,mesh is rivets, while paper tape on un-painted drywall is welding.
so when working over paint,the rules of paper tape do not apply.this comment might make Captain Sheetrock spit beer on his PC screen,but I guess you could use mesh or paper,what ever you prefer.
also,if you are doing major repairs on old plaster,if there are any major cracks,you should carve them out with something.I use to use a old pointed can opener,the ones with the triangle end, used to punch into cans .then prefill those major cracks with durabond or something !!!!
here's a better link for that fiba fuse tape too ,shows it in action http://www.sgtf.com/Brands/FibaFuse/FibaFuseDrywallTape
not a fiba fuse salesmen,have not even used it,on DWT some guys like it,they say it sits real tight against the wall,which makes for easier coating.
hope this helps,and sorry if I started a MESH vs PAPER war on this site:thumbsup:


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## Capt-sheetrock (Feb 10, 2008)

The mesh argument will go on forever
If you want to know if it has any strenght, just grab it in both hands (from the sides and roll it, like bank tellers do with dollar bills). It has no rigidity at all. 
This post was about a corner at the cieling. Mesh is useless in a corner. Since it has no strenght, why use it?? 
Butt joints taped with with mess, will crack,,100% of the time,,, why use it??
Flats don't crack as much with it, but then again, flats finished without any tape at all, seldom crack either.
When you brake it all down,, mesh users like it cause its cheap, fast,and convient. If thats what is important, then yes, mesh is for you.


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## 2buckcanuck (Dec 14, 2010)

Capt-sheetrock said:


> The mesh argument will go on forever
> If you want to know if it has any strenght, just grab it in both hands (from the sides and roll it, like bank tellers do with dollar bills). It has no rigidity at all.
> This post was about a corner at the cieling. Mesh is useless in a corner. Since it has no strenght, why use it??
> Butt joints taped with with mess, will crack,,100% of the time,,, why use it??
> ...


yeah,the thread started out about angle repairs,but then the post slowly turned to plaster repair.guess I should of put metro M&L's question in a quote.so he's working over old plaster with paint on it,in a house I'm assuming has gone through most of it's settelling and movement .paper tape over paint now becomes a adhesive,not a bonding agent on new drywall,in a nut shell he's doing patch work.it's more important he digs out the major cracks and prefills them


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## Capt-sheetrock (Feb 10, 2008)

2buckcanuck said:


> yeah,the thread started out about angle repairs,but then the post slowly turned to plaster repair.guess I should of put metro M&L's question in a quote.so he's working over old plaster with paint on it,in a house I'm assuming has gone through most of it's settelling and movement .paper tape over paint now becomes a adhesive,not a bonding agent on new drywall,in a nut shell he's doing patch work.it's more important he digs out the major cracks and prefills them


Ya know, this thread started out about a problem with the corners in this house. It's caused by truss up-lift. The only fix is to remove the fastners from the lid and then re-finish the joint. 

Somehow it became an arguement about differant products. Don't change the fact that the only fix is to remedy the problem and then re-do. 

Even Home-Depot don't sell a quick fix for this one.


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## TJ Paint (Jun 18, 2009)

2buckcanuck said:


> I'm back
> you guys got me to thinking,your normally repairing over walls that have been painted,so the rules will change for you when using mesh or paper.here's trying to explain without starting a mesh vs tape war on this site.
> mesh tape has a adhesive on one side that ad-hears to the drywall and must have a hotmud applied to give it added strength.
> paper tape in conjunction with a proper taping mud acts as a bonding agent,not just as a adhesive,there is a chemical reaction between the two.to me,if it was metal work,mesh is rivets, while paper tape on un-painted drywall is welding.
> ...


as a painter and not a mud guy, this was a good explanation. Thank you.:thumbsup:

You know, as far as the OP and solution, I'd just caulk it.


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## Capt-sheetrock (Feb 10, 2008)

TJ Paint said:


> as a painter and not a mud guy, this was a good explanation. Thank you.:thumbsup:
> 
> You know, as far as the OP and solution, I'd just caulk it.


 As a drywaller that paints, I problly would too,,,, but since it is gonna crack again next winter,,, I'd use Elasto-meric, cause it don't crack as bad and I could probbly get two years out of the fix. Then the after the callback, I could fix again for another 2 years with 1/2 a tube.

LOL, still won't FIX the problem:thumbsup:


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## 2buckcanuck (Dec 14, 2010)

Capt-sheetrock said:


> As a drywaller that paints, I problly would too,,,, but since it is gonna crack again next winter,,, I'd use Elasto-meric, cause it don't crack as bad and I could probbly get two years out of the fix. Then the after the callback, I could fix again for another 2 years with 1/2 a tube.
> 
> LOL, still won't FIX the problem:thumbsup:


again,go back and read the thread from Metro M&L,the topic changes,which should be no surprise.were no longer on the topic of truss lift ,but on general plaster repair.
I jumped in and answered a question he was asking of you ,sorry
re -read thread :yes:


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## Ardee (Jun 9, 2008)

I agree with using PP(paper and premix). However I'm forced to use mesh and hot mud in high humid areas. Go paper - maybe even double tape it.


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## Capt-sheetrock (Feb 10, 2008)

Ardee said:


> I agree with using PP(paper and premix). However I'm forced to use mesh and hot mud in high humid areas. Go paper - maybe even double tape it.


Who's forceing you to use mesh????? We need names!!!!!


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## Ardee (Jun 9, 2008)

Capt-sheetrock said:


> Who's forceing you to use mesh????? We need names!!!!!


I do a lot off work for a housing management company and mold remedy sometimes comes into play. On mold prevention the supervisor insists(mostly in bathrooms) to use mesh and hot mud. CGC tells me(10 years ago) that sheetrock 45 and mesh tape has better mold resistant properties. As far as code goes or any other authority goes, I have no opinion since I don't do NC anymore.

BTW for the yankees out there CGC = Canadian Gyprum Company. 

If anybody has evidence with or against, let me know.


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## dubinpainting (Feb 16, 2010)

Metro M & L said:


> Ok capt,
> 
> what about the big 36" mesh used for stabilizing old lathe and plaster? I just did six rooms, three coats. Should I have used paper?


Maybe this is just me, but I thought when filling corners where two walls meet, or where ceiling meets wall that you should just gouge out the crack and fill it with mud. It shouldn’t be taped with mesh or paper because it wont last......I don't know if this is true but that's how I have always done it! It has seemed to last for me.


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## Nigel (Dec 30, 2010)

*>>>*

Or just slap some cheap molding up there and paint it white....Day Saved!


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## Capt-sheetrock (Feb 10, 2008)

dubinpainting said:


> Maybe this is just me, but I thought when filling corners where two walls meet, or where ceiling meets wall that you should just gouge out the crack and fill it with mud. It shouldn’t be taped with mesh or paper because it wont last......I don't know if this is true but that's how I have always done it! It has seemed to last for me.


 Again, question is for "how long". I agree, if you are just wanting to get by for a year or too, your method is fine. Nothing wrong with that, or caulk for that matter. 

We got to talking about "what" caused this problem,,, and it WAS for his "Mother-in-law" (that in itself is risky). 

So again,,, are we talking about what the prob is and how to REMEDY it, or how do we fix for "long enough"???

BTW, mesh will never ,,,,,,, nevermind


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