# why does my ceiling look like this?



## Windows on Wash (Aug 30, 2011)

Appears to be a seam between the sheets showing to my eye. 

Any additional weight above that ceiling of late? Moisture changes?


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## jeffmattero76 (Jan 4, 2016)

If you get on a ladder and push on the ceiling does it move? Push on one side of the seam and then the other. If it moves, even a little at the seams, it needs to be re-fastened, preferably with drywall screws, and then spackled, sanded and painted. 

Also, it appears in one of the pictures that there are multiple "creases" as you have described them. If so, try to get an accurate measurement of how far aoart they are.

Do you live in this house year around? If not, do you keep it heated when you are not there?

Sent from my LG-D415 using Tapatalk


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## clarenceboddick (Nov 30, 2016)

Probably an older house that used nails to hold the drywall up. Nails in that application will work loose and let the drywall sag down. Not sure why, but it seems to be common, unless the drywall is covered with a layer of plaster.

To be sure, I'd remove all the old paper tape and use proper drywall screws to secure the drywall. Both at the seams and all over. Then I'd use fiberglass tape instead of paper. I prefer the tape that has fibers that have both 45 and 90 degree angles to each other and I use drywall tape spray adhesive to hold it up. A lot of work, but once done, you wont have to worry about seams cracking anymore.


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## Gary in WA (Mar 11, 2009)

Creasing or ridging would be because the tape is in compression, not tension (stretched out) as a weight placed above- may not apply here though a good idea. "Moisture change" is better- I think; *If *those are trusses and the weather has turned cold to lengthen the top chords and room warm the bottom so ceiling lifts up to show ridges,* fig. 10*; https://buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange Ceiling joists or trusses above?

Fiberglass tape (square holed) is not as strong as paper and it has some "give" or stretching. Paper tape provides greater joint strength around movement and shrinkage. Use Durabond or other chemical drying compound for even greater strength. Links if needed.

Gary


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## bryanp (Aug 24, 2011)

Thanks for all the replies thus far.



Gary in WA said:


> Creasing or ridging would be because the tape is in compression, not tension (stretched out) as a weight placed above- may not apply here though a good idea. "Moisture change" is better- I think; *If *those are trusses and the weather has turned cold to lengthen the top chords and room warm the bottom so ceiling lifts up to show ridges,* fig. 10*; https://buildingscience.com/documents/insights/bsi-023-wood-is-good-but-strange Ceiling joists or trusses above?
> 
> Fiberglass tape (square holed) is not as strong as paper and it has some "give" or stretching. Paper tape provides greater joint strength around movement and shrinkage. Use Durabond or other chemical drying compound for even greater strength. Links if needed.
> 
> Gary


I'm not seeing any water damage currently. And this picture was taken from the first floor of a story house. So, I imagine it's of ceiling joists.



clarenceboddick said:


> Probably an older house that used nails to hold the drywall up. Nails in that application will work loose and let the drywall sag down. Not sure why, but it seems to be common, unless the drywall is covered with a layer of plaster.
> 
> To be sure, I'd remove all the old paper tape and use proper drywall screws to secure the drywall. Both at the seams and all over. Then I'd use fiberglass tape instead of paper. I prefer the tape that has fibers that have both 45 and 90 degree angles to each other and I use drywall tape spray adhesive to hold it up. A lot of work, but once done, you wont have to worry about seams cracking anymore.





jeffmattero76 said:


> If you get on a ladder and push on the ceiling does it move?
> 
> Also, it appears in one of the pictures that there are multiple "creases" as you have described them. If so, try to get an accurate measurement of how far aoart they are.
> 
> Do you live in this house year around? If not, do you keep it heated when you are not there?


Year round yes. We keep the temps: 67 - 71.

I got on a ladder and the two sides seem unmovable.



Windows on Wash said:


> Appears to be a seam between the sheets showing to my eye.
> 
> Any additional weight above that ceiling of late? Moisture changes?


Moisture is a possibility, as the season has changed. This picture was taken from the downstairs of a 2 story house. No additional weight upstairs.


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## Gary in WA (Mar 11, 2009)

So what happened recently since that is when you noticed the buckling? 

Did you start running your heating system more often... or cooking more often with water boiling? Shower/bath running with door open and no bath fan? 

Do you live near a large body of water that would increase the relative humidity in the house? Remodel work on a room below or basement that the stack effect would distribute through the house?

Are you burning a wood heat source or repaired gas furnace? Running a humidifier? These things could add a lot of moisture to increase the RH in the rooms below the ceiling/floor joists and thus "move" the joists- ridging the tape; http://www.thisiscarpentry.com/2010/09/03/moisture-content-wood-movement/

Gary


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