Primers are essential to painting concrete. Do you know when to use it? This crash course covers priming for bare concrete, priming when repainting, and important things to remember when using primer. Ready? Let’s begin.
What is Primer and Why You Need It
Primer is sandwiched between your concrete surface and your paint. When you’re working on bare concrete, you apply it after surface preparation and before your topcoat. But why do you need it?
Primer helps ensure that your topcoat properly adheres to your concrete. In this way, it acts like a sort of glue between your paint and your walls. On top of that, primer also brings out the true color of your topcoat. If you’re painting vibrant yellows, reds, and oranges, you may even need to use special colored primers so you get the intended shade. You’ll see it indicated in the packaging when you buy Boysen paint colors.
Applying Primer on Bare Concrete
Whatever surface you’re working with, primer is applied after you’ve done proper surface preparation procedures. If you’re not sure what surface prep to do for concrete, check out this guide: Surface Preparation: New Concrete.
Once your new surface is prepared, you can apply primer. For this, you have several reliable Boysen primer options.
For concrete interiors
Boysen Permacoat Flat Latex B-701 is the standard primer for interior concrete surfaces. For an eco-friendly option, there’s also Boysen EcoPrimer. It’s certified both lead-safe and low VOC by leading international third-party certification body, SCS Global.
For concrete exteriors
The best option for bare concrete exteriors is Boysen Acrytex Primer. The Acrytex line of products is specially formulated to be long-lasting and able to withstand the Philippines’ harsh sunny and rainy days. Acrytex Primer is watertight, rigid, and gives a strong foundation for paint.
When to Use Primer When Repainting
Let’s say you’re painting on a concrete surface that already has existing paint. Do you still have to apply primer? The overarching rule is that you apply primer on areas where you see bare concrete peeking through. But, of course, there are exceptions.
If your wall’s paint is still in good condition—meaning there are no paint problems like peeling and blistering—you can simply sand the surface lightly and then go directly to applying the topcoat. However, if there are paint problems and treating those problems results in exposing the bare concrete underneath, you will have to prime those areas.
Another instance where you will need to apply primer when repainting is if you’re painting a light color over a darker one. Without primer, you get what’s known as bleeding or when the old layer of paint becomes visible through the new topcoat. For this, you will need to apply primer on the whole area.
Important Points to Remember
First, don’t make the mistake of using the wrong type of primer. There are also primers made for other surfaces like wood and metal. Make sure you’re getting one made for concrete. If you’re not sure which product to go for, the Boysen App has a useful Choose Your Product tool that can give recommendations.
Next, make sure your primer is compatible with your topcoat. The easiest way to do this is to follow what’s shown on your chosen topcoat’s painting schedule. Remember, using incompatible paint products can lead to problems like saponification. One of the common ways this happens is when solvent-based paint, like Boysen Acrytex, is applied on top of water-based paints, like Boysen Permacoat. You can check the painting schedules of Boysen products via the Boysen App as well.
Good luck and happy painting!
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