# why does my walls have these streaks of white???
**URL:** https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581
**Category:** Factual Questions
**Created:** [March 29, 2020, 1:39pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581 "2020-03-29T13:39:18Z")
**Posts on this page:** 16
**Page:** 1
### Author:  [@teddybound](https://boards.straightdope.com/u/teddybound)
#### Post date: [March 29, 2020, 1:39pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/1 "2020-03-29T13:39:18Z")
I have just repainted them (albeit using the same paint) a few months ago…
the previous coat lasted a few years though.
my friend said it could be the paint is poor quality, or old.
I am thinking of buying new paint but want to seek help from here first.
[ ](https://imgur.com/2PbWt5Q)
[ ](https://i.imgur.com/2PbWt5Q.jpg)
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### Author:  [@rbroome](https://boards.straightdope.com/u/rbroome)
#### Post date: [March 29, 2020, 1:55pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/2 "2020-03-29T13:55:02Z")
I have never seen that effect before.
What is the wall made of? Gypsum board? plaster?
To my eye, it is clearly defective paint. Assuming there is nothing significantly different about the wall, that paint was clearly bad.
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### Author:  [@rbroome](https://boards.straightdope.com/u/rbroome)
#### Post date: [March 29, 2020, 1:56pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/3 "2020-03-29T13:56:33Z")
Assuming the wall is OK, you definitely need to use a stain-blocker before you repaint. KILZ is the go-to for this, but check with a paint store. There are some really cool products out there.
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### Author:  [@teddybound](https://boards.straightdope.com/u/teddybound)
#### Post date: [March 29, 2020, 1:58pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/4 "2020-03-29T13:58:26Z")
> [@rbroome](#):
>
> I have never seen that effect before.
> What is the wall made of? Gypsum board? plaster?
>
> To my eye, it is clearly defective paint. Assuming there is nothing significantly different about the wall, that paint was clearly bad.
concrete wall
it lasted ok for several years… then these streaks turned up.
i still had some leftover paint from a few years ago so repainted.
then these streaks emerged after a few months gradually.
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### Author:  [@Chefguy](https://boards.straightdope.com/u/Chefguy)
#### Post date: [March 29, 2020, 2:39pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/5 "2020-03-29T14:39:26Z")
Does the white part feel powdery? It could be [efflorescence](https://www.caaquebec.com/en/at-home/advice/tips-and-tricks/tip-and-trick/show/sujet/efflorescence-how-to-recognize-it-and-take-action-if-need-be/).
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### Author:  [@teddybound](https://boards.straightdope.com/u/teddybound)
#### Post date: [March 29, 2020, 2:48pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/6 "2020-03-29T14:48:05Z")
> [@Chefguy](#):
>
> Does the white part feel powdery? It could be [efflorescence](https://www.caaquebec.com/en/at-home/advice/tips-and-tricks/tip-and-trick/show/sujet/efflorescence-how-to-recognize-it-and-take-action-if-need-be/).
thanks!
it’s not powdery… feels like a stain
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### Author:  [@pjd](https://boards.straightdope.com/u/pjd)
#### Post date: [March 29, 2020, 3:03pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/7 "2020-03-29T15:03:45Z")
Did you stir the paint ?
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### Author:  [@enipla](https://boards.straightdope.com/u/enipla)
#### Post date: [March 29, 2020, 3:10pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/8 "2020-03-29T15:10:57Z")
> [@pjd](#):
>
> Did you stir the paint ?
Seriously, that’s the first thing I thought of too.
You could always blow it off and call it modern art. That’s very weird.
I would show that pic to the paint store guy. Modern paints are great. Expensive, but great.
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### Author:  [@teddybound](https://boards.straightdope.com/u/teddybound)
#### Post date: [March 29, 2020, 3:12pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/9 "2020-03-29T15:12:12Z")
> [@pjd](#):
>
> Did you stir the paint ?
I did… afaik
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### Author:  [@RivkahChaya](https://boards.straightdope.com/u/RivkahChaya)
#### Post date: [March 29, 2020, 3:13pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/10 "2020-03-29T15:13:42Z")
Call the high priest; your house may have leprosy.
Lev. 14:33-57
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### Author:  [@teddybound](https://boards.straightdope.com/u/teddybound)
#### Post date: [March 29, 2020, 3:14pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/11 "2020-03-29T15:14:35Z")
> [@enipla](#):
>
> Seriously, that’s the first thing I thought of too.
>
> You could always blow it off and call it modern art. That’s very weird.
>
> I would show that pic to the paint store guy. Modern paints are great. Expensive, but great.
I want to repaint tbh, and this time to buy new paint.
but i’m worried these stains will reemerge again
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### Author:  [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)
#### Post date: [March 29, 2020, 5:44pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/12 "2020-03-29T17:44:11Z")
If it appeared after several years, then reappeared some months after a repaint, it seems a good sealer/stain-block is needed (as others have said).
Go to a real paint store (i.e. not Lowes or Home Depot) and get a professional opinion and good paint. A good stain blocker + good paint ought to fix it!
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### Author:  [@Chefguy](https://boards.straightdope.com/u/Chefguy)
#### Post date: [March 29, 2020, 7:03pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/13 "2020-03-29T19:03:50Z")
> [@teddybound](#):
>
> I want to repaint tbh, and this time to buy new paint.
>
> but i’m worried these stains will reemerge again
Prime first with [**Kilz**](https://www.kilz.com/). I’ve used the product for years and it provides an excellent barrier between old paint and new. Your walls may have been painted with oil paint and now you’re trying to coat with latex. They’re really not compatible.
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### Author:  [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)
#### Post date: [March 29, 2020, 7:05pm UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/14 "2020-03-29T19:05:47Z")
Kilz would be my first thought to, but give the paint store guys a chance–there are multiple kinds of stain sealers, for different kinds of problems.
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### Author:  [@Saturn\_Dreams](https://boards.straightdope.com/u/Saturn_Dreams)
#### Post date: [March 30, 2020, 5:14am UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/15 "2020-03-30T05:14:54Z")
It would help if you mentioned the kind of paint you used, how you applied it and the environment of the room. Going by the pics, it could be [frosting](https://www.ppgpaints.com/pro/pro-painting-tips/how-to-fix-frosting-issue-on-paint). One way to find out is to wash the streaks with a damp cloth. Does it disappear when wet then reappear when dry? If so, then it’s most likely frosting.
To fix it, you’ll need to apply a waterproofing primer or a resin-based primer before adding a new topcoat. The key is to prevent surface moisture contamination.
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### Author:  [@Folly](https://boards.straightdope.com/u/Folly)
#### Post date: [March 30, 2020, 5:29am UTC](https://boards.straightdope.com/t/why-does-my-walls-have-these-streaks-of-white/850581/16 "2020-03-30T05:29:27Z")
> [@Chefguy](#):
>
> Does the white part feel powdery? It could be [efflorescence](https://www.caaquebec.com/en/at-home/advice/tips-and-tricks/tip-and-trick/show/sujet/efflorescence-how-to-recognize-it-and-take-action-if-need-be/).
One of my favorite words.