One of the indications of a good house painting in Pleasanton job is the quality of paints used. But once the paint job has aged, faded, or sustained a lot of scuffs or scratches, it’s time to make the necessary touch-ups to the affected surfaces of your home. 

However, leftover paint eventually goes bad, so you may end up with several old paint cans just sitting in your storage. Especially if you’re an avid DIY-er, you may have a storage room or closet full of cans of old paint that you don’t want to throw out. However, you’re also not sure whether you will be able to use them. 

If you have old cans of paint sitting around in your closet or storage room, you may be tempted to use them to do the necessary touch-ups for many reasons. You may say to yourself, “It’s such a shame if I just get rid of them,” especially if you find half-full cans of paint. And two, you want to save money by not buying new paints. But how long do these previously used paints last once after they’ve been applied to surfaces?

Not all paints are created equal in terms of how long they will last. Their longevity depends on the ingredients these paints are made of. For instance, an unopened can of latex paint typically lasts 10 years, while an unopened can of oil-based paint lasts up to 15 years. 

But once these cans of paint are opened and used, they can go bad pretty quickly and may only last for one to two years.

Compared to latex and oil-based paints, paints that contain natural ingredients typically have a shorter shelf life. For instance, chalk paints can last up to only a year, while milk-based paints can barely last a week. Store each paint in a cool and dark place to hit the upper end of their lifespan.

Here’s a list of the average lifespan of common paint types:

• Oil-based paint – 2 to 15 years
• Latex paint – 2 to 10 years
• Acrylic paint – 2 to 10 years
• Limewash paint – 5 to 10 years
• Chalk paint – 1 to 5 years
• Milk paint (pre-mixed) — 3 to 5 years
• Milk paint (powdered) — around a week

Factors that affect your paint’s shelf life

There are three factors that can affect the longevity of your paint: air, impurities, and temperature.  

• Air – An unopened and unused can of paint can last up to 10 or 15 years, depending on the type of paint. Once the lid of your paint can is opened and air is introduced to the paint, it will make the paint harden and solidify. A poorly sealed can of paint allows the air to get in, thus shortening your paint’s shelf life from years to months. You may add water to the old paint to increase its lifespan.
• Impurities – Impurities can also affect your paint’s shelf life. Organic material, such as dust, pollen, grass, leaves, etc., will rapidly spoil your paint by turning it rancid or sour smelling. You will know the difference between a new and bad paint by its odor. New paints have a tolerable, “fresh,” and even vaguely sweet smell, while paints that have gone band have a sour and sharp odor.
• Temperature – Paints should be stored in temperatures between 60 to 80 degrees Fahrenheit. Anywhere higher or lower than that temperature range can negatively affect your paint’s longevity.

How to tell if the paint is expired?

You may be tempted to use the remaining half of your old paint, but what if that paint is past its useful life? Here are some signs that indicate that your paint has gone bad:

• Paint that has a rancid or sour odor – After the lid is opened, some types of paint have a sour, foul, or sharp smell. Other paints may smell musty. Once the old paint is applied, the disagreeable odor may lessen over time but not disappear. Rancid or sour odors in your paints likely indicate bacterial growth. If the paints smell bad in the can, they will smell bad on your walls, too.
• Paint with signs of mold – As mentioned before, other paints may smell musty. This means mold or mildew may have likely thrived in your paints. In addition, the obvious mold or mildew spots are a giveaway sign that your paints should be discarded.
• Paint that has been frozen and thawed a lot of times – Frozen paints can be successfully thawed and used as long as they don’t become clumpy and smell foul. However, most paint experts are inclined to agree that freeze-thaw cycles will eventually break the paint down.
• Paint with lumps – While it is natural for latex paints to form a thin film on top after some time if they have solidified past that point and become lumpy or chunky, it’s a sign that the paints have gone bad and thus should be discarded.
• Paint with a jelly-like consistency – If the paints have turned into a jelly-like substance that refuses to blend smoothly, it’s an indication that they are getting past their prime. In that case, you may try adding water to your latex paint or thinner to your oil-based paint to thin out the consistency.

Paint storage tips

If you don’t intend to use your paints again for a long time, consider the following tips to ensure that your paints will not go bad quickly:

• Store the paint in a cool, dark place, in temperatures between 60 to 80 Fahrenheit.
• Keep your paints as tightly sealed as possible to keep them away from impurities, such as leaves, grass, dust, etc.
• Do not allow your paint to freeze.
• Remove all impurities from your paint.
• Add only a small amount of water to your old latex or acrylic paint or thinner to your oil-based paint.
• Once you’re done using your paint, transfer it to a plastic container since rust from the metal cans can contaminate the paint.
• Before closing the lid, place a piece of plastic kitchen wrap over the open container, then firmly tap down the lid. 

If you’re not sure whether you can use your stored paints again or not, don’t hesitate to call professional house painting in Pleasanton experts and obtain no less than a professional’s opinion. Contact the team at Custom Painting, Inc. at 925-294-8062 if you would like to have your home painted.