Temperature & Humidity Requirements for Paper Storage

Old family records, legal documents, your kids' best finger paintings – if you have important papers that you want to preserve for decades to come, creating the right storage conditions is critical. Paper can become brittle, be destroyed by mildew or be eaten by insects if certain temperature and humidity requirements aren't met. That doesn't mean you necessarily have to cart your boxes of important papers to a climate-controlled storage space. There's probably at least one area of your home where the conditions are right for paper storage.

Paper and photos do best in cool temperatures. The maximum recommended temperature for paper storage is 75 degrees Fahrenheit, though some experts recommend a high temperature of 65 degrees.

It's probably not a disaster if papers are stored somewhere that occasionally gets a little warmer, but ideally, they'll be kept at lower temperatures for long-term storage. Heat accelerates the rate at which paper and ink break down. High temperatures also tend to encourage insect activity.

If your family records include photography or film materials, like acetate negatives, color negatives and slides, these items may need to be kept in cold storage (a freezer) for long-term protection.

Humidity control for paper storage is critical because the effect of humidity on paper can permanently ruin your important documents. If papers are stored someplace too humid, they may be destroyed by mold and/or insects. High humidity can also cause papers to permanently change texture and become wavy instead of flat. If the humidity is too low, paper can dry out and become brittle.

Choose a storage space where relative humidity remains below 65 percent but doesn't drop below 15 percent. Ideally, aim for the range of 30 to 50 percent relative humidity. Install a hygometer (humidity gauge) in the room where you store important papers and use a dehumidifier if necessary to keep the space within that range.

Beyond temperature and humidity requirements, think about controlling three other threats to your important papers: insects, light and water.

Even if you get the temperature and humidity conditions just right, insects may still find and feast on your stored papers. Silverfish and certain beetles are very attracted to paper and can do a lot of damage in a short time. Considering you probably don't check on your stored documents very often, insects can destroy an entire box of paper before you discover the problem. Store important papers in plastic storage boxes with locking lids to keep out insects and make sure there are no food sources nearby that could attract insects to the area. Choose storage boxes large enough that every paper can lay flat.

Prolonged light exposure can also damage paper, causing discoloration and fading. Keep storage boxes in a dark place, like a closet, or toss a blanket over them if they're stored in a room with a window. Finally, think about flood risks. Don't store boxes of important records on the floor, where they could be damaged if a pipe breaks. Never store boxes of papers on a garage or basement floor where rainwater or melting snow could reach them. Keep storage boxes on shelves at least a few feet off the ground just to be safe. If you ever deal with flooding in the future, you'll have enough to deal with without mourning the loss of your most important papers.