# cheap paint in bathroom got mold?



## mayhem69 (Aug 1, 2008)

Hi, i am currently remodeling my bathroom. The ceiling was getting a little bit of mold and i am just wondering why. I have a exhaust in the bathroom. The paint we bought a few yrs. ago was cheap and didn't know if that was the cause. It is a semi-gloss from i think sears. I am going to repaint over that, should i use something like killz to paint over the existing? And then apply fresh on top of the killz?


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## slickshift (Aug 25, 2005)

The paint is not _the cause_
But it's not helping either
Kilz is a stain blocker...you won't need that unless you have stains
And (Original Kilz) is is oil-based, so not a good choice here if you do need to block mildew stains

Your best bet is to kill the mold
(well...you _must_ kill it)
Using a homemade bleach/water mix, or a commercial (store-bought) mildecide like X-14 or Moldex

Then you should re-paint with a Kitchen & Bath, or other type of quality mold resistant paint


Use a shellac-based stain blocker (like Zinsser's BIN) if _after_ mildeciding, the mold/mildew has left stains
Then coat with a paint like mentioned above


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## Nestor_Kelebay (Jun 17, 2008)

I wouldn't paint over everything with a primer like KILZ.

I'd:

a) use a 10% solution of bleach in water to kill whatever mildew is growing on your existing paint

b) clean the bleach solution off the walls and ceilings with a sponge and clean water,

c) allow time to dry, and

d) paint over that cheap paint with a paint meant for use in bathrooms like Zinsser's PermaWhite Bathroom Paint tinted whatever colour you want and available at Home Depot and other home centers.


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## markpainter (Nov 15, 2008)

There could be a lot of reasons for the mold from humidity (maybe not since you are ventilated) to a leak. I would use a mold killing solution like Moldex instead of just bleach... bleach should kill it but I'd want to be extra sure it doesn't return. I would recommend B-I-N over Kilz but that will work fine if you already have some on hand an mold leaves behind stains. Get a mold resistant or kitchen/bath paint for the final costs.
__________________
Mark, a Woodbury, MN Painter


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## mayhem69 (Aug 1, 2008)

so do i need to prime over the semi-gloss that is there now? or can i paint right over it with the mold and mildew paint?


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## Nestor_Kelebay (Jun 17, 2008)

mayhem69 said:


> Hi, i am currently remodeling my bathroom. The ceiling was getting a little bit of mold and i am just wondering why. I have a exhaust in the bathroom.


Probably because it wasn't meant for use in bathrooms and therefore doesn't have any mildewcide in it.



> The paint we bought a few yrs. ago was cheap and didn't know if that was the cause. It is a semi-gloss from i think sears. [


Sears paints aren't that bad, but so far as I know, they don't make a paint specifically for bathrooms.



> I am going to repaint over that, should i use something like killz to paint over the existing? And then apply fresh on top of the killz?


No, if it wuz me, I would test the surface to see if there's a soap film on it. Take some ordinary masking tape and stick it to the semigloss you want to paint over. Now pull it off. If it doesn't stick as well as it should, and pulls off more easily than masking tape should, you probably have a soap film on that paint that needs to be cleaned off. In that case, I would:

Buy a bottle of phosphoric acid based bathroom cleaner (ZEP makes a decent one) and use that along with a Magic Eraser to clean the soap film off the paint. Phosphoric acid is typically the active ingredient in bathroom cleaners because it cuts through soap scum like a knife but won't attach chrome finishes.

The, rinse the residual phosphoric acid off the paint with a sponge and water.

If the tape seems to stick fine and puts up a proper fight when you try to pull it off, then I'd just clean the walls with a damp Magic Eraser prior to painting over the semi-gloss with Zinsser's Perma-White Bathroom Paint, which you can buy at Home Depot.


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## mayhem69 (Aug 1, 2008)

i was at Home Depot yesterday and they don't sell the Zinssers bath paint. They just had the primer. Maybe i'll try Lowes or Sherwin Williams. Thanks for all your input guys, we got cultured marble surround tub and shower installed and want the bathroom done right this time. We just did it half ass 10 yrs. ago when we moved in, didn't have much $$ then.


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## Faron79 (Jul 16, 2008)

*Just another choice...*

Good cleaning advice above, but another good bet is Dirtex POWDER.

Usually doesn't need rinsing (unless water is getting moderately dirty), which is the big advantage :yes: over TSP, which has to be rinsed repeatedly.

Once clean & dry, in this case I would prime. 
Use C2-One primer, Zin123, or other top-notch Latex stain-blockers.
* Yep, the Zin Perma-Whites would be a good bet, since extra mildewcide's built in. Warrantied against mildew growth, in the paint film, for 5 yrs. I believe.
* Or, any top-line Satin or Semi-Gloss.
* Use the fan EVERY TIME, AND FOR 10 MINUTES after a shower. Some fans are better than others!

Faron


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## mayhem69 (Aug 1, 2008)

so are you guys saying i should apply a primer over the existing semi-gloss first??


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## Nestor_Kelebay (Jun 17, 2008)

mayhem69 said:


> so are you guys saying i should apply a primer over the existing semi-gloss first??


That's kind of a toss up.

Officially, according to the Paint Quality Institute,

http://www.paintquality.com

If you're painting a latex paint over anything glossier than a satin latex paint, you should sand the old paint down to ensure good adhesion of the subsequent coat of paint.

Primers, however, are made with binders that are chosed because they stick better to smooth surfaces. So, a primer will stick better to a semi-gloss paint than a paint will.

However, latex paints form films by a process called "coalescence", and that coalescence requires a special solvent that causes the plastic binder resins in the new paint to become soft and sticky. Typically, that special solvent (called a "coalescing agent") ALSO causes the surface of the old latex paint to become soft and sticky too, so the two paints stick well to each other. However, there's no guarantee that the coalescing agent in the new paint will soften the surface of the old paint and make it sticky, so you can't count on new latex paint bonding well to old latex paint. You can with flatter paints because even if the old paint doesn't get soft and sticky, it's roughness results in it having a larger surface area, and the same adhesion over a larger area means a stronger bond.

You're right in the transition zone. "Satin" is the supposed "cut off" point where you should sand prior to painting. The problem is that every different paint company has a different idea of how glossy "satin" is. Behr Paints, for example, have an "eggshell" that's downright "FLAT" and some companies have semi-glosses that have about the same sheen as other company's semi-gloss. So, there's no concensus as to how glossy "satin" is. It's kinda like a recipe calling for a "pinch" of garlic, but not saying how big a "pinch" is. The bigger your fingers, the bigger a "pinch".

If it wuz me, I would paint some of your Zinsser's Permawhite on your semi-gloss paint, allow it to dry completely over 2 or 3 days, cut a checkerboard pattern a little less than 2 inches by 2 inches through the Permawhite paint with shallow pressure on a razor, apply some 2 inch wide masking tape to cover the cut pattern in the Permawhite, press the tape down, and then quickly pull the tape off. If more than 3/4 of the paint stays stuck down, or pulls the existing paint off with it, that means you're getting good adhesion to the underlying paint, and you can just paint over paint. If less than 3/4 of the Permawhite stays stuck down, you're not getting as good adhesion as you should, and you should either sand the existing semi-gloss or apply a primer before painting. If you choose to apply a primer, and if it wuz me, I'd use an interior alkyd (oil based) primer only because it'd be less permeable to humidity in the air so that the humidity in the bathroom would stay in the bathroom to be removed by the fan rather than permeate throughout the house.

PS: The checkerboard pattern is how commercial labs test the adhesion of paint (and other coatings).
http://www.gardco.com/pages/adhesion/pa2000kit.html

Alternatively, just paint a small area of your semi-gloss with Permawhite, allow to dry completely and then try scraping it off with a sharp paint scraper or even a fingernail. If it puts up a good fight to stay on, and makes you work to get it off, then you're getting good enough adhesion.


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## Matthewt1970 (Sep 16, 2008)

You shouldn't have to sand. Like Nestor said, latex will stick to latex. When in doubt, we have used this before.










http://www.zinsser.com/product_detail.asp?ProductID=155


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## here4funnow (May 6, 2012)

try bleaching it first to remove mold if its over the shower or hot tub if you may have one there u need more ventulation bigger exuast fan usally does it .


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## chrisn (Dec 23, 2007)

here4funnow said:


> try bleaching it first to remove mold if its over the shower or hot tub if you may have one there u need more ventulation bigger exuast fan usally does it .


 
Thread is 4 years old, I am pretty sure it has been taken care of by now:laughing:


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