If your paint doesn't have a spoiled odor or consistency, you can use it for touchups or new projects—though it may not result in a perfect finished product. "The product might be too thick to apply, and not flow and level to an even finish," says Edrosa. Skinning is another concern with older paint.
One negative effect of using expired paint is that it may not adhere well to surfaces or may peel off easily. The color may also be inconsistent, and the paint may not dry properly. Additionally, expired paint may emit a foul odor, which can be unpleasant and potentially harmful.
Although the bacteria that grow in paints aren't going to be ingested, they break down the compounds in your paint, making it less adherent and leading to streaks and peeling.
As paint ages and sees exposure to oxygen and moisture, it can break down and create more volatile organic compounds (VOCs), which are hazardous to your health. This is the most important reason not to use paint past its expiration date. Foul-smelling paint is usually due to bacterial growth.
If the peeling is due to poor adhesion or surface preparation issues, it is generally possible to paint over it. However, if the peeling is caused by moisture, mold, or other structural issues, addressing the root cause is essential before applying new paint.
What about prep for painting over existing paint? Just clean the walls to remove any dirt, grime and grease, let dry, dust and you're ready to go. No primer needed, just water thin the paint 10% for easier application and better coverage.
You can tell paint has gone bad by the smell and texture. A rancid or sour-smelling paint means your paint has gone bad. In particular, the smell of bad paint is similar to sour milk. Other indicators of expired paint include a lumpy or chunky paint consistency.
If the old paint is flaking, bubbling, or peeling off, it might not be a good idea to paint over it directly. This is because the new layer of paint might not adhere properly to the surface, leading to an unattractive and uneven finish.
Employ Agitation Techniques. Employing a brush or a specialized paint mixer can evenly redistribute the pigments and mediums in dry paints, bringing them back to life. Art Hack: Test the archival quality of revived paint by applying it to a test surface and checking for changes after a week.
One of the best ways to tell if your stored paint has gone bad is to test it on a piece of board or timber. If lumping occurs it could be that chunky sized bits of paint have formed despite a vigorous stir. Extreme bad smell like rotten eggs might be highly concentrated.
The bottom line is that watery paint is unusable. So if your paint is too watery and you attempt to use it to paint your home, you will notice that the paint won't adhere to surface correctly. It will be 'thin' and therefore will perform poorer than expected.
If it smells bad, bypass using the paint entirely — that smell is bacterial growth that will likely persist once it's on the wall. Small flecks or a thicker consistency, however, can be ignored for quick jobs if you're not a perfectionist.
Although opened paint can last up to around two years (if stored properly), you can usually tell if it has spoiled by looking at the expiration date. If however, it gives off a foul, rancid smell you should probably get rid of it (see further down to dispose of stale paint responsibly).
Dangers Of Using Old Paint
In fact, if paint has expired and you use it, it can be harmful to your health. Here's why: The VOCs in the paint products will begin to degrade over time. When you apply the paint to your wall, you put yourself at risk of inhaling these chemicals.
If you don't remove the paint that is currently on the wall then the finished look of your decorating project won't be professional. More often than not, when painting over layers of old paint, the new top layer of paint will be bumpy.
If the current wall is smooth, clean and covered with the same type of paint (both are oil-based for example), you can head straight for the paint. You need to fill holes, spackle and sand*, maybe even cut a new piece of drywall in to the existing wall.
Signs of damage: If the paint has gone bad, it will look curdled like cottage cheese or overly thick like a pudding. If you dig out an old can of paint and you have either of these, it's best not to use the paint and dispose of it properly.
Recycling Your Paint
Sherwin-Williams is pleased to volunteer many of our stores as drop-off locations. Ready to drop off your leftover paint? Search for a Sherwin-Williams store* in any of the participating states/jurisdictions.
Blistering and bubbling paint failure
Blistering is the appearance of bubbles on the painted surface. They are usually caused by moisture which can come from several sources.
Scrape the raised area of the drip. Sand so the surrounding area is completely smooth. Re-prime and re-paint, making sure you feather the new paint into the old.