I have a new painter telling me that a PVA primer is not necessary to use unless it is gloss or semi gloss. I was wondering if this is true, I so my old painter has some explaining to do. He had told me it mast be used on any paint finish over drywall.
Dehumidification is listed as a selling point for HPWHs, but are they actually effective at lowering humidity?
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don't know for sure... but i'm pretty sure the specs say that if your finish is a flat paint.. then you may not need a PVA..
but it's kind of like trying to prove a negative
You'll get a better job with any paint by using a primer first. The primer evens out the absorbtion of the wall (seams vs. drywall, etc.) and seals the paper from fuzzing. Then a light sanding before applying the finish.
The only exception would be some specialty paints that are specifically labeled as being self priming.
PVA primers are a necessity if you want a good paint job over new drywall.
Some universal primers (like Zinsser Bullseye 1-2-3) will do the same thing as a PVA primer, with the added bonus of a quality primer/sealer all in one package.
The purpose of a PVA primer is to even out the absorbtion ratios of the drywall paper, and the mud used for taping/floating/texturing. These two (drywall paper and mud) absorb paint at different rates. If you do not use a primer or PVA primer, then you will most definitely notice the difference in absorbtion between the two. In other words, the mud on the seams will stick out like a sore thumb.
Some paints claim to be "self priming", but I have never had one that would actually do the job of a PVA primer. Even flat paints will let the seam areas look different than the rest of the wall if not sealed with a PVA or similar primer.
Just my opinion, based on many years of painting drywall.
James DuHamel
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Don't get hung up on the term PVA. A primer is just good prep. And no, not everyone uses it. I think you would be hard pressed to find an aesthetic reason for priming under flat paints, but when you get sheens, those can show differently from the paper to mud. Any primer would be better than nothing. And almost any decent primer will accomplish what you want. And yes - evening out the surface is the goal.
I think your old painter knew what was going on and the new guy with his fixation sounds like he read an article somewhere and is the resident expert now.
But there are primers marketed for different things, and using one designed for new drywall is better, and probably cheaper in some instances, than just picking the expensive can.
A little off to the side, if you're interested, look into surfacers. I like Builders Solution (Sherwin) and USG makes a comparable, albeit a little softer product it calls Tuff-Hide. Those not only prime, but as the "surfacer" part implies, gives a uniformity to the surface and fills in minute scratches at the same time. While they advertise it's equivalent to a level V finish, it's not. It is worlds and away superior. I would recommend it if you're either picky about the surface or have a wall where you're going to mate a high sheen paint with a good amount of low angle light bouncing across it.
In calling USG's softer, thats not a dig, just a fact of whats in it. The upside is it sands easier. More like drywall mud. Sanding the bldrs soln is like trying to sand plaster. You can get runs out . . . with some work and a corded sander.
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