We receive countless emails asking about when to use drywall primers with all the talk today about self-priming (paint and primer in one) wall 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 20, 2012 – We are currently in the process of updating this article to include the results of 21 wall primers.
Bare Drywall
The main goal priming bare drywall is sealing and equalizing 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
- seal the porous paper surface
- provide a surface the paint can bond with
- seal the porosity of drywall mud
- 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 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 to “use a primer”. The paint store rep said “use a primer”. It was specified by architects to use a primer. You read online, you read it in magazines, you always heard – “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 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? Yeah, so did we. Did the primer fail? Yeah, 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 wall primers over bare drywall and not one of them performed as well as a drywall sealer such as Zinsser Gardz or three paint and primer in one solutions. Let’s take a look at why this is.
The Test
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 from the left corner doesn't look as nice as the next 24", then you see another 24" that doesn't look as nice as the 2nd area. The 2nd area is 2 coats of eggshell paint directly over bare drywall. The first 24" 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” area on the photo above, the area touched-up will have the sheen of the next 24” 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.
The photo above is Zinsser Gardz drywall sealer applied directly over drywall mud horizontal joint. The sealer absorption into the mud is highly visible. Darker areas reflect deeper sealer penetration throughout the various mud compounds. The next two photos show a horizontal joint with one coat of eggshell paint applied over Gardz.
Again, the sealed portion of the wall seen above reflects shiner as the 1st coat of paint dries slower vs 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
Think back to a time you applied paint directly over bare wood. Do you remember what happens with the paint? Do you recall how much paint absorbed into bare wood? Do you remember applying the second coat of paint and it too absorbed into the bare wood, 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 options.
The photo above shows a wet vertical stripe as the result of two coats of paint over bare drywall. It is clear some acrylic (paint and primer in one) paints perform nicely over bare drywall with solid equalized coverage, appearance and bond. The paint and primer in one used in the above photo outperformed all 14 twenty-one primers with equalizing porosity of bare drywall.
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 20, 2012
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.
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.
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.
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
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 from a particular paint company. 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 wall primer coat 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
To summarize our experience with 21 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 21 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
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 stroke down method will provide a level of finish that is consistent. The finish in the Best Method was done with last stroke down.
EVERYTHING ABOVE THIS LINE was UPDATED February 20, 2012
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
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.
