Does Emulsion Paint Go Off?

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You might be thinking about doing some home DIY or about painting a new room in the home and remember that you have an old tin of emulsion paint long forgotten that could just do the trick. You might be wondering does emulsion paint go off?

While bringing a new look to a room can brighten it up you should be wary of using old opened emulsion for your walls. The truth is that yes emulsion paint can go off, and when it does the smell can be truly rancid. Paint does go bad and you shouldn’t skimp by using old emulsion and instead choose a good high-quality emulsion paint for a professional finish.

Hopefully, we have caught you before you’ve applied the emulsion and you’re not searching this question after wondering where is that rancid smell coming from after you’ve just finished your painting.

emulsion-paint-gone-bad

It happened to one user over at the Cyclechat forum a couple of years ago and the saga was not pretty at all. It’s best to avoid all that trouble and also a user on the Screwfix forum.

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Why Does Emulsion Paint Go Off?

While the shelf life of the paint is many years, it’s usually best for 5+ years if the paint tin has not been opened. While water-based paints like emulsion are fine for a good number of years 2+ when sealed, you may encounter problems when you’ve re-sealed some leftover emulsion in the hope that it can be reused when you finally get round to redoing the bedroom or living room.

Emulsion paint can go off naturally as air mixes with the paint, even when it’s resealed air can still cause issues and react with the tin. Another major cause of turning emulsion paint off is where the emulsion paint is stored. With water-based paints, it’s important that you properly store paint in a cool, stable temperature environment.

A stable temperature will prolong the shelf life of emulsion paint. While it might seem a good idea to store emulsion paint outside in the shed, the changing of temperatures from the heat of summer to the harsh coldness of winter will negatively affect emulsion paint causing it to smell and go bad.

So how long does emulsion paint last without going off? Firstly, always check the paint with the points below but with proper storage, you can often use emulsion paint up to 6 months old but it really depends on the brand of emulsion and how the paints been stored.

How To Tell if Emulsion Paint Has Gone Off?

woman smelling bad paint using hands closing nose
Emulsion paint that goes off usually leaves an unpleasant smell.

There are a couple of ways to tell that emulsion paint has gone off. When was the last time you used the paint? If it was 5 years ago when you originally moved in then just buy a new tin of emulsion. It’s better to be safe than sorry.

  • Open the tin and wait for the smell. If you get a bad smell from the emulsion paint that can be described as souring milk then the paint is no good, chuck it. If it appears to smell normal like emulsion then it might just be fine.
  • Inspect the tin for rust, sometimes metal shards within the paint tin can flake or fall through and enter the paint. Look for any debris. Don’t use if you can see shards or rust or metal.
  • When you first open an old tin of emulsion you will likely see the water from the paint pooling on top. That’s normal so grab a paint stick and give the paint a mix. Look for any discolourations and imperfections.
  • The likely hood of the paint being more watery and having a thinner consistency is to be expected. It won’t be like it is new and you will need to give it a good mix to bring it back to life.

Just be aware that even if the paint smells fine once applied you may start to smell a souring scent as it dries. If that’s the case then the paint has started to turn bad and you may need to seal it again with an additional coat that should eliminate the smell.

Best Place To Store Emulsion Paint

As previously mentioned, you should be storing emulsion paint in a dry, cool, dark place such as a cupboard in a ‘non-essential’ room. What I mean by that is a room that is not affected by constant heat changes. The perfect place is under the stairs or in a cupboard off the hallway.

Avoid places, where there are constant heat fluctuations such as outdoor storage sheds or storage boxes as the heat and cold, can cause the paint to expand and retract. This change will sour emulsion paint a lot faster than proper storage solutions.

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2 thoughts on “Does Emulsion Paint Go Off?”

  1. Ive applied on my ceiling and the smell of the emulsion is rancid what can i do to get rid of smell

    • Hi Stephen, I have exactly the same problem!
      I have painted half of my through lounge ceiling with bad Matt emulsion.

      How have you got on to eliminate the smell!?

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