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canuckjack 01-11-2009 07:30 PM

Zinsser Bathroom Paint
I've tried to find this among the many posts here, but no luck, sorry if it's a repeat question for ya's.

I'm nearing the end of a complete bathroom gut and I'm about ready to paint. I'm looking at using Zinsser bathroom paint for the ceiling. Their product info says that it can can be used as the primer as well, how well does this work? Would I be better using a straight bathroom primer first? This will be covering new drywall and drywall compound.

Secondly, it seems like it'd be good to use it to prime the walls as well, the whole moisture barrier is appealing. My wife picked a Ralph Lauren Regent Metallic paint for the walls, will there be any problem applying this paint on top of the Zinsser? Or is there a better primer to use for the walls? Or is the RL paint going to be a problem in a bathroom? Moisture shouldn't be a huge issue, there's a stand up shower but I've installed a ceiling fan with twice the recommended CFM for the square footage.


Nestor_Kelebay 01-12-2009 12:16 AM

I've never used Zinsser's PermaWhite as it's own primer, but I believe that would be a good idea.

You see, the way this paint works is that it has a powdered mildewcide dissolved in it. That mildewcide has a very high solubility in water, and it's that affinity for water that actually makes it MOVE toward the surface of the paint when there's water on the surface of the paint, or even when there's very high humidity in the air. As it gets to the surface of the paint, it kills any mildew spores on the paint surface before they have a chance to grow, thereby keeping the paint mildew free.

The reason why Zinsser recommends two coats of their PermaWhite paint is so that you have twice as much mildewcide so that the mildewcide reserve lasts twice as long. That is, two coats of paint contain more mildewcide than one coat, and the mildewcide from the first coat will migrate through the top coat as well. So, priming with this paint, and then applying two additional coats will keep your bathroom looking good even longer than 2 coats over a conventional primer.


My wife picked a Ralph Lauren Regent Metallic paint for the walls, will there be any problem applying this paint on top of the Zinsser?
Say what?

If you do that, how is the mildewcide going to get through Ralph's paint to kill the mildew spores that land on IT? The mildewcide has to be MOBILE in the paint binder so that it can migrate to the surface. The mildewcide in the Zinsser's MIGHT be able to migrate through Ralph's paint, but then again it might not. There are very many acrylic resins used to make paints, and I have no idea whether Ralph uses the same acrylic binder as Mr. Zinsser does. Prolly not. So, if you paint over the Zinsser's with Ralph's paint, then there's a real good probability that mildew would still grow on Ralph's paint even with two or three coats of Zinsser's under it.

Normally, mildew growth problems on bathroom walls occur on the ceiling and high up on the walls near the corners (where condensation occurs cuz heat can be lost from that area in two directions simultaneously so it tends to be cooler there). So, if you can't live without the metallic paint, I'd use it on MOST of the wall, but leave the top 12 to 24 inches of wall and the whole ceiling painted with the Zinsser's. If your wife thinks that would look odd, tell her how impressed your friends will be when you can singlehandedly explain WHY you used the paint this way.

Now that you know how this paint works, you'll understand why painting over Zinsser's PermaWhite with Ralph's paint is like putting in a hearing aid, and then turning it off. It doesn't do any good that way, just as the Zinsser's being under the metallic paint won't do any good.

It's the mildewcide and the water resistant binder in the Zinsser's that makes the difference. What primer you use makes much less of a difference. The only advantage in using Zinsser's as it's own primer is that it increases the reserve of mildewcide available so that the paint remains free or mildew for longer.

canuckjack 01-12-2009 08:32 AM

Thanks Nestor, appreciate the info. Sounds like it's definitely my best option for priming/painting the ceiling and we'll see how committed to the RL paint the wife is.

Your point about using it on the walls is well taken; however, the product info states that as well as providing a mildewcide it also "Seals porous surface areas such as new drywall joint compound, flat paint without priming". Here's my thinking, and let me know if I'm way off: if I use it to prime the walls, even though the mildewcide aspect will be wasted if there's ever a mildew problem with the RL (unlikely given the ventilation), the seal that the Zinsser forms behind it should protect the drywall/compound better than a normal primer would. If this is a legimate use of the product my question then is, will there be any issue with trying to use the RL on top of the Zinsser?

Thanks again

slickshift 01-12-2009 03:53 PM

Def. go with an actual primer over raw sheetrock
The "self-priming" of the PW id great, but the Bathroom is the most heinous environment for coatings
The self-priming bath paint merely stacks the deck in your favor, and should not be substituted for actual priming on new const.

A better primer would be a premium product from Benjamin Moore, Sherwin Williams, or Pittsburgh Paints

Any regular latex product will not technically be a moisture barrier

RL paints in general tend to be iffy at best (much of the price you pay is for the name), but they can be applied with a reasonable expectation of success

Nestor_Kelebay 01-13-2009 12:24 AM


Originally Posted by canuckjack (Post 211416)
Here's my thinking, and let me know if I'm way off: if I use it to prime the walls, even though the mildewcide aspect will be wasted if there's ever a mildew problem with the RL (unlikely given the ventilation), the seal that the Zinsser forms behind it should protect the drywall/compound better than a normal primer would.

Well, lemme explain Slickshift's point first: He's saying to use a regular primer because when a company makes a dedicated primer, then they don't have to make compromises. The primer will use a binder resin that sticks best to the substrates it's intended for (like drywall and joint compound as opposed to a surface that's already painted) and the primer will contain huge rocks that are almost large enough to see with the naked eye called "extender pigments". These rocks plug up the porous surfaces of bare drywall and joint compound so that most of the primer remains on top rather than be absorbed into the joint compound and drywall. With a thicker film of primer over those porous substrates, then none of the paint is absorbed and you end up with uniform, thick coat of paint that hides better.

If you can buy Satin and Semi-gloss Zinsser's bathroom paint, then it can't have very much extender pigment in it. That's cuz it's the amount and the fineness of grind of the extender pigments in a paint that determine what gloss it dries to. A flat paint or primer will have lots of coarsely ground extender pigments. A satin or semigloss will have much less extender pigment, and what it has will be very finely ground. So, to plug up a porous surface you need rocks in the paint a bit bigger than the holes you want to plug, and plenty of them so that the least amount of paint gets absorbed before the holes get plugged. Zinsser's paint primes by plugging up the holes in the substrate with paint. You just let that paint dry completely, and add another coat of paint. It's not the best way to do it, but after that first coat, very little paint will be absorbed into the drywall or joint compound, almost all of it'll dry on top of that first coat. And, the third coat won't get absorbed at all.

Also, by their very nature, latex paints are more permeable to humidity than alkyd paints. So, what Slickshift is saying is that using the Zinsser's paint as it's own primer isn't a good idea cuz it won't perform the job of priming as well as a dedicated primer cuz it won't stick as well nor plug up the porosity as well as a dedicated latex primer.

My personal view is that, maybe true it won't stick as good, but how hard does it need to adhere to provide good service? No one's going to be pulling on the paint or scraping at it. Suffice it to say that you won't be the first or last person to use a paint as it's own primer, and people who do that aren't warning others not to, so they're happy with the results. I think you'd never know the difference AFTER two coats of Zinsser's whether you primed the walls with the Zinsser's paint, the BM primer Slickshift suggested, an alkyd primer or your garden variety general purpose drywall primer.

Slickshift is also saying that any latex product isn't going to form a very effective moisture barrier, and the result is that humidity from the bathroom could potentially pass through the the drywall walls and into the rest of the house. There is truth in that; latex primers and paints will allow H2O molecules to pass through them. But, you have to have sufficient humidity getting into the walls to cause problems like mold and mildew growth. Humidity will get into a wall through electrical outlets, wall switches, etc. It'll get into your bathroom walls if you have a recessed mirror or even through your ceiling fan. However, those small amounts of humidity getting into walls and attics don't cause any problems. It's when you have a water leak, or water getting in some place where it can't get out that you have problems. There's latex primers and paints on gazillions of bathroom walls, and most of them will never have a moisture problem.

I know that when I've had paint peeling on a bathroom ceiling (cuz I used a cheap paint), scraping it down, skin coating it with joint compound, sanding smooth and priming with a latex primer and top coating with Zinsser's bathroom paint was sufficient to prevent the peeling problem from recurring. I know the peeling problem was due to inexpensive paint softening up and loosing it's adhesion under humid conditions. It seems to me that if covering that inexpensive paint with Bullseye 123 (a latex primer) and Zinsser's Bathroom paint (a latex paint) was sufficient to prevent the problem from recurring, then those two latex films formed enough of a moisture barrier to prevent peeling of the inexpensive paint they were applied over.

I do disagree with Slickshift's contention that bathrooms are the most heinous environment for coatings. I have 21 bathrooms in my building, and I WAS having paint problems in all of them until I learned a bit about paint and found out that the problems revolved entirely around the fact that I was using inexpensive PVA paints and true oil based paints in them. I wasn't using paints intended for bathrooms. So, I think Slickshift's opinion may be affected by having seen too many bathrooms painted by homeowners who cheaped out on the paint they used in their bathrooms.

Here, if you want the ULTIMATE painting strategy:
1. Prime the walls with an INTERIOR ALKYD primer.
2. Paint over that with two coats of Zinsser's PermaWhite Bathroom paint on the walls and apply a third coat to the ceiling and top 12 to 24 inches of the walls to get the same mildewcide reserve there as if you'd use the Zinsser as a primer!
3. Now apply your metallic RL where you want it, as long as you don't cover the top 12 to 24 inches of the walls or any of the ceiling.

The interior alkyd will plug porosity, stick very well and form a film that's impermeable to humidity. The Zinsser's will kill any mildew IF it grows through the RL paint before it can start growing on the alkyd primer or into the drywall or joint compound. And, the RL paint will impress your friends and neighbors that you could afford Ralph Lauren paint and still eat meat on Sundays.

Not sure if I answered your question. I think you'll get good results that will last a very long time whichever primer you use, but I do agree that Slickshift's point that a dedicated primer will do the job of priming better than Zinsser's Bathroom paint will. I don't agree that it'll ever make a material difference, tho. It's not like you're going to have a problem using the Zinsser's, you just won't have the warm fuzzy feeling you get from using the best product for the job at every point in the work. But you'll never know the difference unless I told you that.


If this is a legimate use of the product my question then is, will there be any issue with trying to use the RL on top of the Zinsser?
I wouldn't anticipate having any more problems painting RL over Zinssers than you'd have painting anyone's paint over anyone else's paint. Both are still latex paints and they still form a film exactly the same way. So, if you know how latex paints form films, then you'll know that the RL SHOULD stick well to Zinsser's or any other latex paints. I would, however, use the Satin Zinsser's or give the Semigloss Zinsser's a light sanding before painting over it with the RL paint for maximum adhesion, tho. (It'd bond to the underlying Zinssers better simply because by sanding, you provide more contact area between the two paints. Same adhesion over a larger contact area per square inch of surface area amounts to "better" adhesion.)

Hope I answered your question(s). There's more shades of grey here than there are blacks and whites.

jerry omara 08-27-2012 12:02 AM

Benjamin Moore fresh start primer 02300 for sheet rock is a good primer and you can have a mildacide added to the primer or zinzer makes a primer called smart primer both products are latex a mil decide can be added to both and Ralph Lauren paint can also have a mil decide added or use the perma-white as a primer and R/L top coat with a mil decide added either way you should be ok with the finished product.:):thumbsup:

Brushjockey 08-27-2012 05:18 AM

Even though the info is good, know that they are probably done with the project.
This thread is from 09...

MEE123 08-27-2012 08:00 AM

Smart prime isn't latex, it's a water soluable alkyd; like advance.

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