How to Protect Old Family Photos in a Storage Unit

To protect old family photos in a storage unit, pack them in acid-free boxes with a plastic liner, choose a climate-controlled unit if one is available, keep the boxes off the floor and away from exterior walls, add silica gel packets to manage humidity, and check on them twice a year. A storage unit is built to hold furniture and boxes, not to hold a stable temperature or humidity, so photos need more protection there than they would on a closet shelf at home. Here's what actually matters and what you can skip.

Why a storage unit is harder on photos than a closet

A garage or a standard storage unit can swing well past 90°F in summer and below freezing in winter, with humidity that spikes after a hot day or a heavy rain. Photos hold up best in a narrow band, roughly 65 to 70°F and 30 to 50% humidity, and it's the swings that do the damage more than any single extreme. Heat and moisture cycling warps prints, fuses negatives to their sleeves, and feeds mold on anything packed too tightly to breathe. None of this shows up on the first visit. It shows up a year or two later as brittle corners, a musty smell, or prints stuck together.

Climate-controlled vs standard units

If a climate-controlled unit is available and the cost difference is small, it's worth it for anything you'd genuinely miss: original prints, negatives, slides, and albums that can't be replaced. A standard unit can still work for photos that are otherwise well packed, as long as you keep boxes off the concrete floor, away from exterior walls where temperature swings hardest, and toward the middle or back of the unit rather than near the roll-up door. Furniture and other boxes around them also help buffer the swings, as long as nothing damp or chemical-smelling sits close by.

How to pack photos for a storage unit

Use the same materials you'd use at home, acid-free and lignin-free boxes with photo sleeves or archival envelopes inside, then add a step a closet doesn't need: line the box with a plastic bag or a purpose-made liner before sealing it, so a leak or a spike in humidity doesn't reach the prints directly. Tuck in a few silica gel packets to soak up moisture without sealing the box completely airtight, since photos still need some airflow to avoid trapping condensation. Label each box on the side, not just the top, so you can identify it without unstacking everything, and keep the most irreplaceable prints in the box you'd grab first if you ever needed to.

What to check when you visit

Twice a year is enough for most units, more often in a humid climate or right after an unusually hot or wet stretch. Open a box and look for a musty smell, any softness in the cardboard, or prints that have started to stick together, all early signs of moisture getting in. Check that nothing has shifted to touch the floor or an exterior wall, and swap out silica gel packets once they feel saturated rather than dry. Our guide on storing old family photos covers the same materials and target range for a home closet, if the unit is a temporary stop before the photos come back into the house.

Don't let the unit be the only copy

However well a box is packed, a storage unit is still one location. Scan or photograph the prints before they go into storage, or during one of your check-in visits, and keep the digital files in at least two other places. Our guide on how long digital photos last covers keeping those files safe once they exist, and our guide on turning old photos into a video is a good project for the ones you pull out to scan, since a photo that's been digitized and watched is worth more than one that's simply been kept.