PVA (polyvinyl acetate) primer is mainly used on unpainted drywall. Unlike other primers, PVA seals the pores on drywall which makes painting easier.
It contains an adhesive that allows the paint to stick perfectly to drywall. PVA primer has many unique features and uses. But can you apply it over painted walls? That’s what we are going to discuss in today’s article.
Can You Use PVA Primer on Painted Walls?
Even though PVA primer is mainly formulated for unpainted drywall, it can also be used over painted walls. However, for you to apply PVA primer on a painted wall, it must be thoroughly prepared.
It should be free of stains, flakes, and dirt. This will minimize the risk of failure and ensure better adhesion between the old paint and the PVA primer.
Reasons Why You May Use PVA Primer on Painted Walls
Painted walls usually don’t need PVA primer. But there are a few scenarios where you may need to use it. The most obvious reason is to promote the adhesion of old and new paint.
Due to the presence of an adhesive in PVA primer, it can ensure a strong bond between old and new paint. This will guarantee the longevity of the paint on the walls.
The other reason why you may use PVA primer on painted walls is if you intend to paint a light color over a darker one.
If you were to use paint alone, you would need many coats to hide the dark color. But with PVA, the dark colors should be concealed with a few coats thus saving both time and paint.
Which is Better for Painted Walls – PVA Primer or Paint Sealers?
When working on an already-painted wall, you are better off using a paint sealer than a PVA primer. Though most people often confuse primers and sealers, the latter is ideal for reconditioning old surfaces that are unsuitable for painting.
In this case, that’s a painted wall. Therefore, do not be surprised to come across expert recommendations that you should use sealers when dealing with painted walls.
What are the Risks of Applying PVA Primer on Painted Walls?
Before brushing PVA primer on an already-painted wall, you must understand some of the risks involved. In the worst-case scenario, the PVA primer could fail and you would have to restart the project from scratch.
Sometimes, when the PVA primer dries, it may have a crocodile effect. This is when paint cracks and resembles the pattern of a crocodile or alligator’s skin.
These two outcomes are mostly attributed to not preparing the surface of the painted wall thoroughly before the application of PVA primer.
If you must use this type of primer on a painted wall, it’s crucial that your scrape off any flaking and clean dirt on the surface. This guarantees maximum and flawless adhesion.
Another factor that increases the risk of PVA primer failure is if the wall has glossy paint. You need to remember that PVA primer is formulated for porous surfaces.
On a glossy surface, it may not penetrate deeper into the wall which can fail. Therefore, if your painted wall is glossy. You must scuff it up first before applying PVA primer.
What Should You Do If You Accidentally Used PVA Primer on a Painted Wall?
You don’t need to be alarmed as long as you have adequately prepared the surface. However, if you had applied the PVA primer directly over the painted wall, you may experience a few problems later.
If you are not a professional painter, this is a mistake that you can easily make and that’s understandable. However, before you go much further with your project, you need to be sure about what you are doing.
I would highly recommend sanding the PVA primer and starting from scratch. Doing so allows you to correct any mistakes you may have made during the surface preparation stage. You also get to avoid issues such as the crocodile effect or total paint failure.
So, if you have accidentally applied PVA primer on a painted wall, take a step back and evaluate the risks. You can then decide whether to continue or start over which I highly recommend.
How to Apply PVA Primer on Painted Walls?
Now that you know the benefits and risks, let’s go through the process of how you can apply PVA primer over painted walls;
Step 1: Preparation
This is perhaps the most important step when laying PVA primer over a painted wall. Start by scraping any loose and flaky paint. Thoroughly clean the surface to remove dirt and impurities. Give the wall enough time to dry.
If the painted wall is glossy, you can sand it lightly to create something for the PVA primer to bite into. Also, if there are holes or cracks on the painted wall, now would be the best time for you to fill them up.
Step 2: Application
Mix the PVA primer according to the manufacturer’s instructions. This is very important as it determines the adhesion and effectiveness of the primer.
Once you are done mixing it, you can apply it using an airless sprayer or a roller brush. If you are going to use a brush, make sure that it’s a high-quality brush.
Spread the PVA primer uniformly over the painted wall. PVA primers usually dry within three to four hours. However, give it at least a day before adding the second coat. After it dries, you can proceed to add fresh paint over the wall.
How Many Coats of PVA Primer Should You Apply Over a Painted Wall?
Just because there is some old paint on the walls, that doesn’t mean you need 10 coats of PVA primer to cover it up. Two or three coats of PVA primer are usually enough for a painted wall.
Provided the painted wall is adequately prepared and cleaned, the first coat will fill and seal any pores on the surface. the second coat will promote better adhesion to the top coats. Most of the time you don’t even need a third coat.
Can PVA Primer Hide Old Paint Stains?
One thing most people forget is that PVA primer doesn’t offer color coverage. Yes, it may dilute the stains but it will not hide them completely. That’s the job of the new paint you will apply over the painted wall.
So, if you are worried about old paint stains still showing through the PVA primer first and second coats, just give it time to dry and proceed to laying the top coats. By the end of your painting project, the old stains will be completely covered.
Is It Advisable for You to Use PVA Primer on Painted Walls?
Throughout this article, I have been very specific about the recommended surface on which PVA primer should be used, which is unpainted drywall.
I have also mentioned that PVA primer can be used on painted walls as long as they are prepared thoroughly. These are two crucial things you have to keep in mind if you are considering engaging in such a project.
Online, you will come across conflicting opinions regarding the use of PVA primer on painted walls. However, at the end of the day, it’s up to you to decide the best approach.
From a professional point of view, I wouldn’t recommend PVA primer as the first choice when working on a painted wall.
Instead, I would recommend using a paint sealer with high tenacity. Such a sealer would create a stronger adhesion between the old painted wall and the new paint.
However, due to certain reasons, you can only access PVA primer. Go ahead and use it but follow the instructions I shared with you earlier.