Dec 20, 2008

Drywall primers... again!

bare drywall

We receive countless emails asking about when to use drywall primers with all the talk today about self-priming (Paint and Primer in One) paints. We’ve also received comments from paint contractors on our YouTube videos saying we should use wall primers on bare drywall rather than applying wall paint directly over drywall. What do they know that I don’t? Let’s take a closer look at wall primers and their purpose. What is wall primer supposed to do?

UPDATE: FEBRUARY 11, 2015 – This page is updated.

Bare Drywall

The main goal priming bare drywall is to seal and equalize the porosity between the surface drywall paper and a variety of drywall compounds and toppings (collectively muds) to provide a solid foundation for paint to bond. We also want wall primer to provide a solid uniform sheen for finish coats of paint, including flat paints. Continuously painting new construction homes allows us to expose a whole host of product limitations which otherwise may or may not be noticeable painting previously painted surfaces.

Our goal has four parts

  1. seal the porous paper surface
  2. provide a surface the paint can bond with
  3. seal the porosity of drywall mud
  4. prevent top coat sheen degradation

What can go wrong using drywall primer

  • poor adhesion to drywall
  • poor gloss retention of finish product
  • poor equalization of porosity between mud and drywall
  • poor touch-up ability
  • poor clean-up / scrubbing durability

What if paint does not bond with primer? What if primer does not bond with drywall? What if primer bonds with bare drywall, but has poor adhesion over drywall mud? What do you do now? You primed right? The paint isn’t sticking that well is it? Did you try a tape test or maybe you tried washing it and the paint and primer came off back to bare drywall? Did you remove the masking tape from the baseboard and it tore paint and primer off the wall exposing bare drywall?

The label on the paint can says, “Use primer.” The paint store rep said, “Use a primer.” It was specified by architects to, Use primer." You read online, you read it in magazines, you always hear – “Use a primer,” and you did. Not only that, but you used the paint manufacturers recommended primer on the back of the paint can.

So now what? Is it too late? You may already have a coat of paint over the primer, but its the primer not sticking, not the paint. Was the drywall surface clean? Did you remove drywall dust left behind from sanding? Did you shop-vac the drywall and the paint still didn’t stick? Did you try wiping down the drywall with a damp sponge? So did we. Did the primer fail? So did ours. Did we do something wrong?

Lucky for you, we have all the answers and before you get discouraged we also have a fix so you can achieve that finish and bond you initially tried to achieve.

We tested a total of 14, now 21 32 wall primers over bare drywall. Not one of the drywall primers performed as good as a drywall sealer such as, Zinsser Gardz or three Paint and Primer in One solutions. Let’s take a look at why that is.

The Test

drywall primer

Try performing the test for yourself. Let’s say for example you have a piece of bare drywall sitting on your lap and 1 tablespoon of water and 1 tablespoon of any wall primer of your choice, there are tons of them out there, pick one.

Now, take the tablespoon of water and slowly pour it on the drywall. The water dissipates into the drywall right? Now take the tablespoon of primer and do the same. Not exactly the same result is it?

If you want to dive deeper into testing, try this test over bare drywall mud, it will provide similar results with a completely different effect with the primer.

Try this small test too. Take a sanded drywall patch, clean it, dust it, vac it, damp sponge it if you want and run your finger over it when its dry. I suspect your finger will have a white dusty powder on it.

What this test tell us is, no matter how good you clean new drywall for paint, there is only one thing that will prepare it to accept paint. Apply a sealer that will penetrate both the paper and the mud and bond all of it together. Thinner material penetrates better – right?

Notice in the photo above, the first 24-inches inches from the left corner doesn't look as nice as the next 24-inches. Then you see another 24-inches that doesn't look as nice as the second area. The second area is 2 coats of eggshell paint applied directly over bare drywall. The first 24-inches is primer plus one coat of eggshell paint.

Sheen degradation

One major set-back as a result of using a wall primer is finish sheen degradation. Some primers are better than others but nonetheless, some sheen will absorb into the primer coat. The loss of sheen is very apparent in the photo above. If we were to make a touch-up on the first 24-inch area on the photo above, the area touched-up will have the sheen of the next 24-inch in that photo because the touch-up is still building the true sheen of the paint because true sheen was never achieved with the 1 primer, 1 finish approach.

drywall sealer

The photo above is Zinsser Gardz drywall sealer applied directly over the bare drywall mud on a horizontal joint. The sealer absorption into the mud is highly visible. Darker areas reflect deeper penetration throughout the various mud compounds. The next two photos show a horizontal joint with one coat of eggshell paint applied over Gardz.

Zinsser Gardz
drywall sealer

Again, the sealed portion of the wall seen above reflects shiner as the 1st coat of paint dries slower  compared to areas without sealer. Absorption rates are minimized over properly sealed areas, (also seen in the solid wet vertical stripe below). However the photo below is 2 coats of paint applied directly over bare drywall. The vertical wet stripe seen below is taking longer to dry in comparison to the wall primer used to the left and right of the stripe.

Primer vs. Paint

drywall primer

Think back to a time when you applied paint directly over bare wood. Do you remember what happened with the paint? Do you recall how much paint absorbed into the bare wood? Do you remember applying the second coat of paint and it too absorbed into the bare wood. Maybe even three coats looked questionable?

Have a look at the specific details on the wall primer tests performed in the photo above.

The same thing happens when you apply paint over bare drywall. Exactly the same thing, but with varied results depending on the paint used.

Some wall paints penetrate, seal, and equalize the porosity of bare drywall better than wall primers, providing better adhesion and also look great with 2 coats of paint applied over bare drywall. So here we have a classic case of Good, Better and Best.

The photo above shows a wet vertical stripe as the result of two coats of paint over bare drywall. It is obvious some 100% acrylic (paint and primer in one) paints perform great over bare drywall with solid equalized coverage, appearance, and bond. The paint and primer in one used in the above photo outperformed all 32 drywall primers.

UPDATE: February 11, 2015


Looking at the photo above, could you honestly say a primer is needed over bare drywall if I can achieve coverage, adhesion, and equalization with a paint far better than wall primer? I'm saying... knock yourself out. If you feel you have the desire to waste money and labor on a primer coat and leave yourself open to failure, then do it.

But let’s take a look at what is best, because that is what this site is all about.

Best

UPDATE: February 11, 2015
Many new products have arrived on store shelves since this article was first published back in 2008. Read this next section carefully and read over the previous sections if you skipped them.

drywall sealer

In regards to Level 5 finishing on walls with high light reflection, the best product known to me for bare drywall is Zinsser Gardz. I see primers fail all the time. The number of painters writing in about primers somewhat confirms their results are not what they expected after using wall primers.

Back Camera 

Apply Gardz directly over bare drywall, then apply 2 coats of paint for best results. Remember this is new drywall and you need to build a foundation, so use 2 coats of paint. Think about this, even with one coat of Gardz, and 2 coats of paint, your total dried mil thickness is minimal at best. The photo above is 1 coat of Gardz, 1 coat of eggshell paint (seen wet). The photo was taken on the portion of the wall where the horizontal mud joint in the previous photos were taken.

Zinsser Gardz

Gardz is a thin water-like clear sealer and most of the product will dissipate into the fibers of the drywall and mud. Gardz is similar to injecting glue into drywall and mud. This is why in the previous photo above you see a very nice uniform finish with one coat of Gardz and one coat of paint. These results are far greater than any wall primer we’ve ever used.

Gardz in comparison to typical wall primers

drywall primer

The photo above is one coat of drywall primer and 3 coats of flat wall paint over new drywall. The lack of equalization between drywall mud and drywall is common with wall primers. Interesting to note: this is the top of the line product. It is expensive in materials and labor to perform a primer and 3 coat system only to have it fail to do what you set out to accomplish. Coincidentally, what you see in the photo above is exactly what the 1st coat of primer looked like.

If the coat of wall primer looked like the photo above, and the photo above is 3 coats of flat paint over wall primer—what have you accomplished by applying 4 coats? Nothing. What if you can apply masking tape to the 1 primer, 3 coats of flat paint and pull the paint and primer off to expose bare drywall again? What have you accomplished by applying 4 coats? Nothing.

Painting walls with high reflective values

Let's say you get a call, their house is a few years old with builder grade flat paint on the walls and the homeowners want to paint the 16' high foyer wall extending to the back of the house (windows on both ends). Applying an eggshell over some builder flat paints will typically dry fast and may be difficult to achieve a uniform finish. Your best bet here is to apply Zinsser Gardz over the builder flat and proceed with one or two coats of eggshell paint. Painting over Gardz extends the working time of paint to cover large surfaces with ease. In general, an entire 12x12 room can be rolled entirely and upon completion, the first area rolled remains wet. Extended drying time is required as paint dries on the surface of Gardz.

Better

paint and primer in one

To summarize our experience with 32 wall primers, we have not found one wall primer to date that adheres to bare drywall using simple tape testing. Having said that, there are many wall paints that fail the same test when applied directly over bare drywall. So what exactly are we accomplishing by using a wall primer vs wall paint?

We found a few wall paints with better adhesion than all 32 primers tested over bare drywall. The only problem you may experience is a need for a 3rd coat, but one primer coat, plus two coats of wall paint is a total of three coats anyway, but you can achieve better adhesion with some paints. To be fair, the other argument to applying 2 coats directly to bare drywall is achieving a uniform sheen with eggshell or semi gloss. But think about this, 1 primer and 2 finish is 3 coats.

The photo above shows one particular flat enamel wall paint (center of photo) applied directly to bare drywall in two coats has a nicer true sheen appearance vs two primer options to the left and better than another flat wall paint to the right. Coat for coat, the paint and primer in one solution is the winner here.

Good

wall primer

The low cost route is using an inexpensive primer over bare drywall and applying one coat of wall paint. There are advantages and disadvantages utilizing this method.

Typical Uses

One primer, one finish is typically used as a low cost solution when a flat finish is required and level of quality is ignored.

Advantages

  • Primer can be considerably less expensive than paint
  • One primer coat, one flat coat of paint can produce cosmetic results
  • One tinted primer coat and one coat of finish can be applied but you lose adhesion or bond some of us need to tape off walls, hang wallpaper over and even wash or scrub depending on what your paint allows.

Disadvantages

  • Uniform finish may not be achieved
  • Typically of less quality
  • Poor adhesion to bare drywall
  • Poor scrubability aspects
  • Poor touch-ups
  • one primer, one eggshell may have poor appearance and touch-ups are likely to show

Remember when you landed the job, the homeowner told you she will be hanging wallpaper later? Do you shortcut her at this point or prepare the job now for paper later? What if its you hanging the wallpaper? Too many guys are doing the "right-for-now" work instead of what is best for down-the-road work.

Primer typically requires MORE attention to rolling than wall paint. If primer is rolled any old way - you may never get the finish to look right no matter how many coats of finish. Here is a video rolling walls. Utilizing the last pass down method will provide a consistent finish. The finish in the Best Method was done with last pass down.

EVERYTHING ABOVE THIS LINE was UPDATED February 11, 2015

Something to think about

Something to think about for those of you spraying commercial work. Think about how much you can save on materials utilizing a better method. What is that high-build primer suppose to be shot at… 20 mil thick? Spraying walls inherently wastes materials and can be near twice as much vs rolling it.

Here is an interesting tid bit. Same two houses done two different ways. One guy sprayed the walls with 60 gallons and the other rolled it with 15. The guy spraying had a guy back rolling too. What a huge waste of time and money and an extra guy. Guy spraying spent $1,380 on materials and the guy who rolled it spent $345 There was no difference in workmanship.

Funny how a certain manufacturer makes an executive decision to create a primer that requires such a heavy layer be applied cover bare drywall. But that same question also begs the question, was a product like that designed because guys don't know how to paint or does the manufacturer not know how to make a product that works without laying it on as heavy. If you apply anything at 20 mil, it better look good.

The argument

440i My argument with using a wall primer is the lack of a fail-safe method and I need that in my business. While I enjoy the 440i I received from a paint store due to primer failing, I am not going to have another homeowner come back to me complaining she washed the paint and primer off the wall and obviously this has happened to me otherwise I wouldn’t be posting a fix to this problem online. I have a ton of information and previous test on wall primers. Do a Google search on jackpauhl+wall primers or click this link.

The Fix

So let’s say you too fell sucker to the “use a primer” method and you are in that same situation where the paint washes off the wall or you had to apply masking tape to do some wild painting scheme seen on TV. There is a fix and leave it to no other than Zinsser to have your back! Zinsser Gardz can be used to apply over a paint that was previously undercoated with primer utilizing the Good method above. Gardz assists with penetrating through paint and the primer and help with bonding them to the drywall and not only that but moving forward with a new coat of paint will give you the ultimate finish you see in the Best method above.

19 comments:

George M. Lambrinos said...

Thanks for this post!

Can I add mildewcide to Zinsser Gardz and my paint or should I only add it to my paint? I'm finishing a basement and trying to take every precaution

Gee said...

I am doing a DIY job in my dining room. I've read the Gardz arguements, and, after removing wallpaper, I applied Gardz and two skim coats. I'm going for a smooth texture, and there are some small flaws in the wall (very small, very shallow). I want something that will level the flaws. I plan to apply Gardz over the skim coats (per Gardz instructions) in any case, but I would like to know if and which primer I need to level the minor imperfections. Or if a high quality paint (thinking about the SW Duration, but, again, which one?) will have some leveling qualities and I can omit a primer (after the Gardz, of course)? Please help! I've done this before and hate the texture/quality, and I want to do this right!

Dantihesis said...

Haven't used Gardz, but Peel Stop works too.
Back in the early '80s most paint I used said on the back, to use a primer or this paint. I always used the paint and not a primer. No call backs. When I first started using primer over existing paints or bare drywall or Kilz Premium (absolute worst primer I've ever used for cure time) on bare wood is when I started having problems. One exception to this is when I use Coverstain over bare drywall or existing paint. From my experience, oil primers impregnate themselves into the bare drywall and wood, making for a tight bond of the top coat. No Kilz.
On to skimming an eggshell paint job the owner did over slightly textured wallpaper and repaint it. Probably just reseal with CoverStain or PeelStop. Maybe no primer. Zinsser knows their stuff.
P.S. Your captcha isn't showing all the time. Tried the handicapped version, that failed and brought forth the letters to type in. Just a square with question mark in it.
Using latest Safari browser on OS X 6.8

njvondra said...

Are you saying in some situations you would use a penetrating paint instead of primer? Would you like to share which paints performed better than the primers? Do you have any favorites?

hesh said...

does this aricle apply to plaster walls too? i removed wall paper from two bedrooms then primed with an oil based stain block primer(killz) the patched and taped cracks then primed again and after paiting 2 coats the touch ups are still visible!! what now? guardz and 2 more coats of paint???

Jack said...

@hesh The article is specific to drywall. You should be fine with your Kilz selection over plaster if it was Kilz Original primer.

I'm not sure what you are seeing when you say touch ups are still visible. Do you see the patch through the touch up or are you seeing the actual touch up not blending?

Some paints do not touch up good and require a full surface recoat to resolve an issue.

Melissa Mann said...

Continuing on Gee's previous comment, do you ever apply a primer over the Gardz to level out any minor surface imperfections or is the Gardz/2 finish coats typically adequate?

Melissa Mann said...

Continuing on Gee's previous comment, do you ever apply a primer over the Gardz to level out any minor surface imperfections or is the Gardz/2 finish coats typically adequate?

Dantihesis said...

Nice update to this article.
Thanks for sharing it.

Dantihesis said...

Nice update to this article.
Thanks for sharing.

R said...

So what brand paint+primer performed the best over all others? Would be very helpful. :)

R said...

Which primer+paint performed better than all the others as you said in your blog.
Would like to know so I can buy and begin my painting :)

Bebe said...

My house had popcorn ceilings AND walls that I have had covered with a careful few layers of drywall mud. So, there is no drywall paper involved, just thick mud. I will eventually wallpaper some of the walls. Do you recommend the Zinsser Gardz, then paint, for this situation, or the paint-with-built-in-primer? Also, what is best prep for mud before wallpaper? Do I even need the paint? Thanks.

James Paterson said...

Not sure if anyone is replying anymore as this is an old thread. Very interesting though!

I recently moved into a 35 year old home, where once we started prepping for a fresh coat of paint, the old paint all peeled off at every gyprock joint, only where the mud/setting compound was used, over all walls and ceiling. once past the mud, the original pain stuck to the raw gyprock. I peeled back the old paint, featherd the edges, and used Dulux Acrylic sealer undercoat with ultra smooth to help hide the ridges of old paint. But it proceeded to peel off as well.
Im just about to move up stairs and start a new area, would a coat of Peel Stop over the old paint and existing mud joints give the old paint some extra adhesion before I apply a new top coat?

Hopefully someone is still keeping track of this Blog haha...

Cheers.

Brian Havanas said...

James. No. It will not help. Failing paint is failing paint. It will continue to fail no matter what you apply over it. If any product had a chance it would be Gardz because it is very thin and can be forced into and behind loose paint.

Kent said...

I recently primed new drywall walls for a basement room with a SW latex primer and then had to mask with painter's tape in order to spray paint the ceiling. Significant primer peels off when I removed the tape from any of the green mold-resistant drywall boards that I used. I'm concerned about painting over this but the idea of trying to remove all the primer by sanding or some other means and then re-priming turns my stomach. I contacted Zinsser to ask whether Gardz would help this situation but they advised against it and said that it likely will bond to the faulty primer. But your article suggests this works for you? Can you advise? Thanks

Kevin Purdy said...

What is the cure time for a latex primer? I was told 30days by paint sales people. Who can wait that long to go to the next step? Felt i was getting the brush-off when asking about the problems with primers. I will try your advise next time i paint. Thanks!

Brian Havanas said...

I know the feeling Kevin. Each product is different as far as cure times, but more important would be recoat time. How long after applying primer can paint be applied over it. You'll find that info on the can. Head over to jackpauhl.proboards.com for more discussion on primers.

LizzieH said...

Remodeling a modern house. It had horrible orange peel texture. It now has layers of mud..smooth. I decided to experiment with a basement bedroom to see how the primer and paint would look. The paint store recommended Speedhide. At first they sold me the MaxPrime Latex Primer/Sealer. It really soaked in. I went back for another gallon, and they sold me the Quick-Drying Latex Sealer. They were concerned if I wanted a smooth finish that the MaxPrime might cause too much build up. I'm reading more about MaxPrime, now, and I think it actually would have helped hide more imperfections and pin holes. Regardless, the sheen on the walls is awful. Very uneven. Looks like I either missed rolling over areas (which i didn't) or the primer soaked in better in various spots. I'm afraid to paint the walls. I bet it will take two coats and I already have two coats of primer. Should I try the Zinnser Guardz? Should i just move to another room and try the Zinnser? This is a large house and I must get this primer down just right. Can't keep waste more time and money. Thank you.