# Drywall discolored, no water damage.



## cone13cone (May 1, 2009)

Recently I received a call to look into a "leak". When the homeowner pointed out the leak to me it was to say the least like nothing I have ever seen. There was a perfect discolored rectangle etched, if you will, into the ceiling(popcorn). It almost reminded me of an overexposed picture. I went up into the attic and found that directly over this discolored rectangle there was missing insulation. So I am fairly certain that this discoloration is directly related to the missing insulation, but my question is has anyone ever encountered anything like this? And if so what causes the discoloration? Is it varying temperature, moisture related, or something else. 

Thanks,
John


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## Tim0282 (Dec 11, 2007)

Most likely moisture from the insulation being moved. Moisture will go to the coldest spot. so you have condensation. Viola, the texture will have moisture damage just like a leak in the roof or plumbing.


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## cone13cone (May 1, 2009)

Tim0282 said:


> Most likely moisture from the insulation being moved. Moisture will go to the coldest spot. so you have condensation. Viola, the texture will have moisture damage just like a leak in the roof or plumbing.


I was actually leaning away from moisture damage, as the popcorn texture is perfectly intact. There is no change in the consistency of the texture, unless this is the result of such a small amount of moisture over the course of years I don't think it is moisture. Sorry I don't have pictures but its almost as if a faint shadow is being cast on the ceiling.


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## Tim0282 (Dec 11, 2007)

It would be a very small amount of moisture involved and would probably not affect the texture, just change the color. The cold-warm air transfer would just cause condensation. I think the rock would soak up the moisture and just change the color. But, without seeing it, it is hard to tell for sure. The humidity in the house would go right to a cold spot.


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## ClosetPro (Apr 29, 2009)

Not a previous patch of an old register maybe?


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## Leo G (May 12, 2005)

With no insulation there there was likely no vapor barrier. If there was no vapor barrier then slight amounts of water vapor will travel through the drywall. When the dry wall is slightly moist (5-6% more than the surrounding) then the dust in the air will stick to it more readily. After a long time the accumulated dust in that one area will make it darker than the surrounding areas. Simple.


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## Frankawitz (Jun 17, 2006)

What causes those dark stains on building interior walls & ceilings? Photos & text identify thermal tracking, thermal bridging, air bypass leaks, insulation defects and air movement in buildings 
Thermal tracking stains or dark thermal ghosting stains indoors indicate building air movement, air leaks, and points of heat loss which increase home heating or cooling cost 
How to recognize poorly insulated building walls or ceilings and how to pinpoint building air leaks
A photo-guide to common indoor ceiling and wall stains and what they mean 
Why & how thermal tracking and ghosting stains could indicate very dangerous carbon monoxide hazards in a building 
Soot from natural gas, LP gas, or oil burners - sooting gas appliances are dangerous 
Thermal tracking marks can indicate thermal bridging: locations of building heat loss 
Links to more photos of indoor ceiling or wall stains that are not toxic mold
Heres the link it came from 
http://inspectapedia.com/

www.frankawitz.net


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## Tim0282 (Dec 11, 2007)

Isn't that what I said in layman's terms? Well sort of...:jester:


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## A+ Texture (Sep 23, 2008)

I agree with tim, replace the insulation. Then I heard kilz has a upright spray paint can thats off white to simulate aged popcorn or mud. I would look into that and paint over it. While your at it look into franks link there too, thats good info.


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