Can You Gloss Over Emulsion Paint?

Today we have a slightly controversial and combated question. The question of the day is if you can gloss over emulsion paint. This is a bit of a complicated question that we'll dive more in-depth into, but I'll do you a solid and give the basic answer up top. In short, yes you can , but it's not a good idea for your paint's long-term health.

You can gloss over emulsion, but it will not result in a long-lasting, high quality finished look. If you're in a bind, it can be done, but it's not great.

There's a bit of background information that you'll need to know before this really makes sense, so let's dive right in, shall we?

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Emulsion Paints and Undercoats: The Basics

Let's start with what exactly emulsion paint is, because that will explain a lot of what I could say for me. And it's always good to know how the things you use work. Knowing why things work and don't will help you greatly in future projects.

Emulsion Paints

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Emulsion is a water-based paint that's mainly used for walls and ceilings inside. While it can be used outdoors, it's not super common. It's called emulsion paint because it's very thick when you get it - first you need to thin with water and emulsify it. For the uninformed, emulsification is, basically, a fancy term for slowly mixing two substances. You know vinaigrettes and mayonnaise? Yeah, they use the same technique to blend into a cohesive single liquid (or weird solid/liquid hybrid, in the case of mayonnaise).

Emulsion paint dries faster than oil-based paints and can go on in just about any way you can imagine. They're great for interiors and ceilings because of how quickly they dry and their resistance to moisture. While it can hold onto woodwork as an undercoat or, worse, a primer (gross) that's not its job .

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Undercoats & Primer

Let's begin by explaining (contrary to what some may tell you) that undercoats and primer are not the same thing .

Primer is a protective layer and seal for the underlying woodwork, while an undercoat is designed to create an even surface before a finish or final paint coat.

Primer is designed to stick to a surface much more than regular paint, and emulsion paints stick drastically better to primer than just about anything else. An undercoat can also act as a protective layer, but its primary job is to create an ideal final painting surface.

Why Not to Use Emulsion Paint as Undercoat or Primer

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Now that we know what each of these things is, hopefully it's a bit more clear why it's not a great practise to use emulsion as a primer or undercoat. In case it's not, let's break it down a bit more.

1. Priming and undercoating are not emulsion paint’s job. Emulsion paints are not designed to do these things. So yes, they can do it, but not well.
2. Emulsion is difficult to get even strokes for an ideal final coat. Undercoat goes on in a thin, even layer, and that’s near-impossible to achieve with basic emulsion paint.
   • Because emulsion is so thick, it’s also much more difficult to sand down. That means you’ll have a drastically less even final coat.
3. Emulsion won’t stick to wood surfaces because, again, that’s not its job. It needs primer to stick long-term.
4. Emulsion is water based. Gloss is oil-based. Water and oil do not mix.

I Want a Gloss Finish - What Now?

Okay - you're dead-set on a gloss finish for your home, but your walls are painted with emulsion paint. What should you do now? Easy (well, not really), repaint! Yes - that means you'll need to remove the paint and go through the whole process all over again . Isn't owning a home fun!?

Removing Emulsion Paint

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We actually just published a super short article detailing this , but I'll go over it once more briefly as a refresher. You'll need protective gear (for you and your floor), some paint remover, a paint scraper, and hands for scrapin'. Now:

1. Put on your protective goggles and gloves and lay down plastic sheeting.
2. Apply paint stripper (or boiled vinegar) with a brush to the paint you want to remove. Allow it to sit for ~30 minutes.
3. Scrape at an angle (as close to flush with the wall as possible), removing paint in strips.
4. Read your paint remover's instructions, some require this step to use soap and water. Now, using warm water (maybe soap) and a sponge, wipe down your walls.
5. Allow it to dry and safely dispose of your paint scraps.

Repainting With Gloss

Now that you've removed the emulsion undercoat, it's time to apply the proper primer and undercoat for a high-gloss paint. To repaint with gloss paint, do the following:

1. Sand down your walls with fine-grit sandpaper, ensuring it’s absolutely as smooth as possible. It is vital that you sand your walls first, otherwise the gloss will not look right.
2. Using an oil-based primer, apply a layer of primer to your wall in thin coats. Allow the primer to dry fully before continuing.
3. Paint your high-gloss paint in thin layers, using a high-quality roller or spray gun (if you have one). Using a paintbrush is likely to result in clear brushstrokes – which you don’t want. You’re going to be applying 2-3 coats over the course of several days, as the paint needs to be fully dry before each subsequent layer goes on.
   • If you don’t allow the paint to dry, it will end up still wet and trapped between the primer and paint. This is a great place for bacteria and mould to grow – so do it right.
4. Success!

Final Thoughts

All in all, that was a bit of a long article, wasn't it? While the long answer to whether or not you can gloss over emulsion is above, the short answer is yes, but you shouldn't . You can also ride a cow, but that's not really the best way to get to work, is it? In other words, just because you can doesn't mean you should .

Gloss paint is a finicky medium that generally needs a professional's hand. If you plan on cutting out the middle man, you'll need to remove the emulsion paint, reprime and resand your wall, and repaint in the right way. Emulsion paint is water-based, while gloss is oil-based. In case you didn't know, those don't really mix well. Add in that emulsion paint won't likely stick to woodwork or drywall without primer, and it's pretty clear what the right thing to do here is.