"Paint that is beyond its shelf life can develop a rancid, sometimes rotten-egg odor," says Edrosa. If you open a can and find either of these problems, dispose of the paint and buy new.
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.
Expired or bad house paint may exhibit signs such as a foul odor, clumping, separation, or a thick, rubbery texture. Mold growth, curdling, or an unusual color change are also indicators. Always check the label for the recommended shelf life and storage instructions.
Oil based paints have a shelf life of anywhere from 2 to 15 years. Depending how well it was sealed and stored. 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.
Paint cans are designed to keep paint fresh for a long period of time. However, once a can is opened, the paint will gradually start to dry out. The process of paint spoiling is accelerated by high temperatures and low humidity levels. In general, an opened can of paint will remain usable for up to two years.
Latex-based paint can go bad, but it takes a while. You'll probably be able to keep it for up to ten years, with a few caveats.
We've got the scoop on why old paint smells so bad and it is simply a buildup of bacteria and mould that causes it to smell like sour milk (OR MUCH WORSE). Bacteria sometimes gets into the paint from the manufacturer but it is most likely to becomes contaminated once opened.
Regardless of which type of craft paint you choose, look for paints that are non-toxic and have the Art and Creative Materials Institute's AP (Approved Product) seal. Another indicator of safe craft paint is the “ASTM D-4236” code.
“We do not have expiration dates on [Sherwin-Williams] paint but we do give it a shelf life of three years (most architectural coatings) from the time of manufacturing,” says Sherwin-Williams' Director of Product Excellence Dennis Fiorilli.
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.
Paint Shake and Re-Tints
If you bring your old paint to a Home Depot paint center, you can have it shaken up in their machines. This saves the effort of stirring up your old paint, but it also sets up another great service: paint re-tints.
Signs of damage:
If it smells unpleasant or you see mold, you will need to discard it (correctly). And, yes, mold can grow inside a paint can and be a serious health hazard if you put it up on your walls. However, if the paint has an ammonia smell, it's still good. Give it a good stir and try it.
How Do I Paint Over Painted Walls? If the wall is in good condition and the paints are chemically the same (both latex, for instance), you have a few options when the new paint is the opposite shade of the old paint. You can use a primer to thoroughly cover the old color, then apply 1 or 2 coats of the new paint.
Both can work, but acrylic paint's elasticity and resistance to wear and tear make it better for high-touch areas and furniture. Latex paint works well for larger indoor projects where low toxicity and easy cleanup with a brush are priorities.
It can be dangerous to use old paint. Paints made prior to 1978 may contain lead and expired oil-based paints can emit harmful fumes that are toxic.
The good news is that if you have an unopened can of paint that has been stored properly, it's almost guaranteed to still be fine to use. Unopened latex and water-based acrylic paints can last up to 10 years and alkyd and oil-based paints can last up to 15 years.
In general, paint fumes will remain toxic for up to a day after the paint is dried. This means being around stored paint, which doesn't really dry, or constantly using paint at work, can result in constant exposure.
Since CO has no odor, color or taste, it cannot be detected by our senses. This means that dangerous concentrations of the gas can build up indoors and humans have no way to detect the problem until they become ill.
Even still, paint odors can linger in a room for up to 4 months as the paint fully cures. During this time, the dried paint's chemical components release Volatile Organic Compounds (VOCs) into the air.
While paints dry to the touch/re-coat within a matter of hours, most paints do not fully cure for up to 30 days. Paint is most sensitive within the 30-day curing process, so it is important to use caution with newly painted surfaces.
Open cans of paint don't last as long, but if the can is sealed after painting and stored in a cool, dry location, such as a heated garage or a basement, the paint can last for years. On average, paint lasts about ten years before it needs to be tossed, although some paint products may last up to fifteen years.
If your acrylic or house paint has dried up, don't worry – you can bring it back to life. Simply add a bit of water or a paint conditioner to the dried paint and stir it well. Start with a small amount, mix, and check the consistency. Repeat until it reaches the desired smoothness.
Impacts on Texture and Finish
If the paint is too thick straight out of the can, it may need to be thinned using the appropriate thinner (water for latex paint, mineral spirits for oil-based paint, etc.) to reach the right consistency.