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piperfection 07-15-2010 10:55 AM

Painting PVC wainscoting
Home Depot carries the Plastpro PVC wainscoting. I'm looking at using this in a bathroom with a 1" hex honed marble floor to get a particular look. In some ways it makes sense to have a PVC product in a bathroom. However: I want to paint it. I spoke with a technical rep for Plastpro and he said that yes, it can be painted. He recommended first cleaning it with Proclean Professional Prep Wash, then priming with Behr waterbased primer and then painting with Behr premium water-based enamel.

But, dang, I'm so skeptical. Painting PVC? Really? Am I nuts? Isn't the paint going to start gradually peeling away in a few years, and then a bit more, and then a bit more until the guys in the white coats come to take me away?

Anyone ever tried this?


Launchpad 07-15-2010 05:59 PM

I have installed a few of these and so far the paint has held up very well. Actually the paint helps with the static that will attract all the dust in the room to the plastic if it's left bare.

We normally just do a good wipe down and paint with a Latex base. No primer. Not sure if that is the right way, but that's how we have been doing it.

After drying, I have yet to see the paint peel from any of the wainscoting we have installed. I have seen it peel from newly installed WOOD wainscot, which was probably more of a moisture issue with the wood.

Nestor_Kelebay 07-15-2010 06:13 PM


Originally Posted by piperfection (Post 46613)
Home Depot carries the Plastpro PVC wainscoting. I'm looking at using this in a bathroom with a 1" hex honed marble floor to get a particular look. In some ways it makes sense to have a PVC product in a bathroom. However: I want to paint it. I spoke with a technical rep for Plastpro and he said that yes, it can be painted. He recommended first cleaning it with Proclean Professional Prep Wash, then priming with Behr waterbased primer and then painting with Behr premium water-based enamel.

I'd be reluctant to go with a small mosaic tile like 1 inch hex to make a floor that looks like it came straight out of the 1930's. The reason why is that most of the problems with ceramic tile are associated with cleaning the grout. So, you can minimize the problems you have with ceramic tile by, if nothing else, minimizing the amount of grout you have to deal with. But, any small mosaic tile is going to have a ton of grout to deal with, and in my view, that's just not a good idea. Better to go with big tiles and less grout.

Yes, PVC can be painted, and it's done all the time. People paint over PVC siding to change the colour of their house. Window manufacturers will always recommend against painting PVC window frames, but it's not because paint won't stick to PVC. It's because PVC has a fairly low "Glass Transition Temperature", which is the midpoint of the temperature range over which it transforms from a hard, brittle material to a soft flexible material. Because PVC can get pretty warm sitting in the Sun all day long, window manufacturers will make their windows out of white PVC and recommend that they not be painted to keep the PVC as cool (and therefore as hard and strong) as possible, thereby minimizing the amount of deformation of the PVC that occurs in service.

However, the guy you talked to was generously kind to Behr, and it's probably because he felt like a duck in an aligator swamp being in Home Depot and surrounded by Behr paint. Basically, ANY latex or oil based primer will stick well to PVC. However, oil based primers tend to stick better to smooth surfaces than latex primer, and some primers are made specifically to stick to smooth surfaces, such as Zinsser's Bullseye 123 Latex primer. The only thing I don't like about Bullseye 123 is that it's so sticky that it sticks to masking tape so well that pulling off the masking tape will also often result in your pulling off the dried Bullseye 123. But, the point here is that you'd do better with an oil based primer or, if you're concerned about adhesion, to use a sticky primer like Bullseye 123.

And, so far as the top coat goes, any paint will do there as well. Since this is inside a bathroom, I'd recommend you go with a paint made specifically for bathrooms, like Zinsser's PermaWhite Bathroom Paint. The reason why is that humidity can cause inexpensive latex paints to become soft and lose their adhesion. When you see paint peeling on the ceiling or high up in the corner where the ceiling meets the wall in a bathroom, the reason is generally not insufficient prep work. The reason is most often that the paint used was an inexpensive paint that used a vinyl acrylic binder, rather than a better quality paint that used a 100% acrylic binder. Paints with 100% acrylic binder stand up to moisture and humidity much better than paints that use a vinyl acrylic binder, and by using a paint specifically made for bathrooms, you know you're getting a paint where the binder is especially resistant to moisture and humidity.

I'm willing to bet dollars to donuts that the guy who recommended you top coat with Behr premium water-based enamel doesn't know what an "enamel" paint actually is. (Post again if you want to know yourself.)


But, dang, I'm so skeptical. Painting PVC? Really? Am I nuts? Isn't the paint going to start gradually peeling away in a few years, and then a bit more, and then a bit more until the guys in the white coats come to take me away?
If you use the wrong paint, all of that can happen.

tomstruble 07-15-2010 09:11 PM

the thing you need to rememder is while the paint will feel dry on pvc it can take up to a month for it to actually cure,so it will be kinda fragile till yhen

Nestor_Kelebay 07-16-2010 11:05 PM


I think you're talking about crosslinking latex paints.

(Lemme explain this.)

Crosslinking latex paints (like latex floor paints) will typically take up to a month to fully cure, but most latex paints don't crosslink. Typically you find that the higher quality interior latex wall paints and ALL latex floor paints (where hardness is most important) will have acrylic binders which crosslink, but most latex paints form a film through a process called "coalescence". That is, most latex paints stop at "coalescence". Crosslinking latex paints go through that same coalescence process to form a film, but then also form chemical linkages within that paint film. The coalescence both kinds of latex paints go through is a physical transformation that doesn't involve any chemical reactions at all. Only the crosslinking latex paints have chemical reactions in that secondary crosslinking part of their curing process.

A normal latex paint consists of a SLURRY of tiny hard clear particles of either white wood glue or Plexiglas and solid coloured particles (called "coloured pigments") and solid white or clear particles (called "extender pigments") suspended in a solution of water and low volatility water soluble solvent called a "coalescing agent" or "coalescing solvent". So, 5 things; hard clear plastic binder particles, solid coloured particles and huge massive rocks almost large enough to see with the naked eye all suspended in a mixture of water and a slow to evaporate water soluble solvent... that's primarily what's in a can of latex paint.

When you first apply the latex paint to a wall, the first thing that happens is the water in it starts to evaporate. As a result, the tiny clear hard plastic particles (called "resins" or "binder resins") find themselves surrounded by the coaleascing solvent at an ever increasing concentration. The coalescing solvent dissolves into those hard clear binder resins making them soft and mushy. Then, the same forces that cause tiny water droplets to coalesce into large drops of rain inside the clowds (capillary pressure and surface tension) also act to cause these soft mushy resins to coalesce together so that you end up with a continuous film of soft mushy clear plastic with the coloured pigments and extender pigments suspended inside it very much like raisins in raisin bread. Then, as the coalescing solvents evaporate out of the paint film (and you begin to smell that "freshly painted smell" in the air which is in most cases a solvent called "Texanol")), the clear plastic hardens back up again to the same hardness it was before that film formation started, and the plastic consisted of tiny clear hard particles in suspension in a liquid.

The above is what MOST latex paints do to earn a living. Once the coalescing solvent evaporates from the latex paint, filling the room with that "freshly painted smell", then film formation is complete, and that latex paint won't change at all (except that the glycerine added when tinting the paint will still evaporate from it, but that won't change any of the paint film's properties significantly).

A cross linking latex paint will go through that same film formation process, but then chemical bonds will form between reactive groups on the surface of the resins, and those additional chemical bonds that form between neighboring resins act just like a roll cage in a racing car, making the film harder (if you were to squeeze it) and stronger (if you were to stretch it).

In both a regular and a crosslinking latex paint, coalescence only takes one to two days and film formation is complete within 3 to 4 days. (Film formation is only complete when the plastic film is as hard as it should be, and that only happens once all the coalescing solvents have evaporated.) It's that additional crosslinking that goes on after film formation in crosslinking latex paints that will take up to a month.

Typically, the top of the line interior latex paints will use cross linking resins because those paints will ALSO use very hard extender pigments (like pulverized silica sand instead of chaulk or talc). If you want a paint to stand up to hard scrubbing without losing it's gloss, then you have to make the paint with BOTH hard extender pigments and a binder that dries hard and strong. Having hard extender pigments in a soft binder will result in the hard extender pigments being rubbed off the paint film and won't work any better than having soft extender pigments in a hard binder as both will be worn down by scrubbing. You need both the extender pigments and the binder to be hard and strong for the paint to stand up to hard scrubbing. So, in top quality paints, they'll use a very hard extender pigment (like pulverized silica sand) and the hardest and stongest latex binder resins you can get, which are the cross linking ones.

And, of course, on a working surface like a floor, hardness is paramount in importance. The harder the floor paint, the less it will be damaged by foot traffic, and the longer it'll stay looking new. So, every paint company will use it's hardest drying paint to make floor paint. Unfortunately, latex floor paints will be made with crosslinking acrylic resins, but still won't be sufficiently hard to provide the same level of performance we've come to expect from oil based floor paints.

You can learn more than you need or want to know about latex paints (and a little about oil based paints) at the Paint Quality Institute's web site at:

(To get to the good stuff, click on the Media Center link next to the red Home link. Then click on the PQI Publications link to get to this page:
Download and read the two PDF files entitled: "The Ingredients of Paint and Their Impact on Paint Properties" and "How Colour is Affected by the Ingredients of Paint". If you read and understand those two brochures, you'll know more about latex paints than most people that work in paint stores.)

The Paint Quality Institute was established by the Rohm & Haas Company, which, until they became a subsidiary of Dow Chemical, were the largest manufacturer of the plastic called "polymethyl methacrylate" in North America. You probably know that plastic better by the name "Plexiglas", "Lucite", or "Perspex", depending on which chemical company made it. Polymethyl methacrylate is the plastic used to make binders for top quality latex paints, so using a top quality latex paint will result in a film of Plexiglas on your walls! Lesser quality or "budget priced" latex paints will use a different binder made from a plastic called "polyvinyl acetate". Polyvinyl acetate is also the plastic used to make white wood glue, and in fact many of the problems associated with using budget priced paints are associated with the fact that white wood glue has a very low resistance to moisture and humidity. Elmer's white wood glue, polyvinyl acetate concrete bonding agents, acrylic nail polish, acrylic grout sealers, acrylic floor "wax" and acrylic (or "latex") caulks all use that same "coalescence" film formation process described above that latex paints do, although they the resins used to make a glue or a caulk or a nail polish will be different from the ones chosen to make a paint. In the paint manufacturing industry, paints made with polymethyl methacrylate (Plexiglas) binder resins will be called "100% Acrylic" paints, whereas paints made with polyvinyl acetate resins will be called "Vinyl Acrylic" paints. However, there are hundreds of different kinds of "100% Acrylic" and "Vinyl Acrylic" resins each with it's own characteristics, so don't think that the wording "100% Acrylic" on a can of paint means that you're wasting your money buying a more expensive paint. "100% Acrylic" on a can of paint means exactly the same thing as "100% Cow" on a package of meat does. What's inside might me prime rib or dog food depending on WHICH acrylic resin the paint was made with.

In the case at hand, it's doubtful that any paint made specifically for use in bathrooms would also use a crosslinking latex resin. That's because the resin they'd choose to make a bathroom paint would be chosen according to it's resistance to moisture and humidity, as well as how mobile the mildewcide would be in that binder. So, hardness and scrubbability wouldn't be important considerations in picking a binder resin for making a bathroom paint. (How often do you clean your painted bathroom walls and ceiling?)

If the original poster were to use a top quality interior wall paint instead of one specifically made for bathrooms, then you'd be correct in telling him it'd take up to a month to fully harden (cuz it would probably use a crosslinking binder). A bathroom paint will use the binder most resistant to moisture and humidity, not the binder that forms the hardest film.

tomstruble 07-17-2010 04:08 PM

wow...why thank you for setting me staight Mr.Kelebay:beer:

oldognewtrick 07-17-2010 04:33 PM

Nestor kept this post relatively short..... this time.

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