Paint storage is an age old question. You want to keep some paint handy for future touch-ups, and it seems crazy to throw out anything that could be of use later. The problem is, there are invisible risks with the storage of paint. From potential vapor explosions to the decay of the paint itself, old paint can behave in unpredictable ways. It might be better to simply get rid of it, but if you must keep some, here are some steps towards reducing those risks.
Paint is designed to be used when fresh, and any unused amounts of it should be taken away from where people live. Once a can of paint is opened, it’s hard to reseal it to the perfect level it was sealed when the paint was originally purchased. During the painting job itself, paint invariably gets in and around the seal between the lid and the can, sometimes becoming partially dry, and thus interfering with a good clean seal later. This may allow vapors to leach out slowly over time. As the temperature of the can changes from season to season, or even from one day to the next, the pressure of the can’s contents may change, allowing those vapors to escape, possibly. The amount might be tiny, but why risk it? If you do decide to store paint at your residence, store it in a shed, away from the house, if you have one.
Many garages, attached to the house or otherwise, are not heated in the winter, nor cooled in the summer. It could be a comfortable seventy degrees outside, a bit cooler inside your house, but a veritable sauna inside your garage. That’s because many garages are not insulated. The roof and loft space over them might be, but the garage itself can work like a greenhouse. The heat gets trapped inside, and the contents of it are heated and cooled as the temperature spikes and troughs with each success day-night cycle. Now imagine those cans of leftover paint, each gallon can with only a half inch of paint in the bottom of it. As the can heats up, vapors in the ‘empty’ space of the can heat up and build up great pressure. A can, under these circumstances, may explode. Combine that with the temperatures, and you may have a small fire, especially if the vapors short out an electrical outlet or fuse box. It’s all downhill from there, as a small fire in your garage turns into a big fire in your garage, and now threatens the whole house. Such a fire, if it were to occur that way, would probably happen mid-afternoon when the heat is at its greatest. Will you be there to call the fire department with plenty of time, or must it be a huge, raging house fire before a neighbor notices and calls for help?
Another popular place to store unused paint is under the house. That is, in the basement or storage area not used by the occupants. Here, if vapors do leak from a paint can, they can go directly into the air everyone is breathing. Not safe.
At least in the garage, paint is somewhat remote from your actual house, and if it is a detached garage or shed, well, any fire that occurs is less likely to become a problem. A basement or other storage area inside the house is more dangerous.
Just like in airplanes, where a fuel tank that is almost empty is more likely to explode than a full one, a full can of paint especially if it was never opened, is a lesser risk than a can of paint that is mostly empty. There simply is no room for vapors to build up, and it takes longer for a container to heat up if it is full. It’s why a turkey, being bigger than a chicken, take longer to cook than a chicken.
Most paints are also sold in five-dollar sample sizes. For most people, that sample size is more than enough paint to cover any eventuality in the future. In most cases, people never ever go back and dig out old paint to do a touch-up job later. It simply sits in the garage for twelve years before it finally gets discarded. But it you simply must have some paint on hand for any future touch-up, you can get small, latte sized cans for that purpose. They may, in fact, be cheaper than an actual latter of the same size!
Be sure to document on the can what the paint was used for. Five years later, you might not remember which color was used on which room, or wall within a room. Use a fine point Sharpie to write on the can where that paint was used, including the date. You’ll thank yourself – and me – years from now if you do, and it will always make a home easier to sell, as prospective buyers will appreciate the care and attention to detail you took on your home project.
Even if a paint manufacturer no longer makes that exact color – satin eggshell morning desert beige – they will likely have an equivalent. And most paint sellers have the means to mix a paint to match an exact color your bring to them. Do you remember that TV ad where the customer arrives at the paint store with a purple bowling ball? They scanned it and the computer worked out the mix needed for the one-off, exact color. Well, this means you will be able to get hold of any color you’d like.
In conclusion, I would say you never need to store any paint. It will be easy to get hold of a fresh supply even decades later. And besides, most people never come back to do a touch-up, so all you’re doing is cluttering up your living space with stuff you will never use.
Be safe, and choose colors wisely!
image by russn_fckr