Water is the worst enemy of books, so store them above ground level, away from leaks, in sealed containers, and if one gets wet, stand it upright, fan the pages open and dry it in a well-ventilated place without applying heat. Insects, rodents, mould, fire and sunlight are the other threats, and each has a simple defence: sealed bins, low humidity, a fireproof container and a spot away from windows.
Part of Collection & Preservation
Paper lasts centuries when it stays dry and is destroyed in days when it does not, so protection decides whether a salvaged library is worth the trip.
Five Enemies, Five Defences
- Water. The worst enemy. A wet book grows mould quickly. Store books above ground level and away from leaks. If a book is wet, stand it upright, fan the pages open and dry it in a well-ventilated place. Heat warps and cracks it. If mould has started, interleave the pages with paper towels and dry the book as quickly as possible.
- Insects and rodents. Silverfish eat paper and binding glue, cockroaches eat nearly everything, and mice and rats chew books for nesting material. Store books in sealed containers: plastic bins with tight lids, ammunition cans or metal cabinets. Cedar chips or dried lavender are mild repellents; traps and cats handle rodents.
- Mould. It needs moisture, with relative humidity above 60%, and warmth. Control humidity with silica gel in sealed containers, and give open shelving air circulation.
- Fire. Books burn. Keep the most critical references in a fireproof container such as a safe, a metal ammunition can or a metal filing cabinet. A buried cache of irreplaceable references needs a waterproof container.
- Sunlight. Ultraviolet light fades ink and degrades paper over years. Store books away from windows. It is a long-term concern more than an immediate one.
Method: Setting Up A Store
Step 1: Choose a dry room above ground. Off the floor, away from exterior walls and roof leaks.
Step 2: Use sealed containers. Bins, cans or cabinets with tight lids.
Step 3: Add silica gel. In each sealed container, to hold humidity down.
Step 4: Separate the critical copies. Fireproof storage for the few that cannot be replaced; a second copy elsewhere.
Step 5: Inspect. Look for damp, mould, droppings and chewing, and fix the cause.
Common Mistakes
- Drying a wet book with heat. It warps and cracks.
- Stacking books on the floor of a cellar. Damp reaches them first.
- Burying a cache in a container that is not waterproof.
Safety
Mould, fire and chemical repellents
Mouldy books release spores that irritate the lungs, so wear a mask when handling them. Do not use stoves, lamps or candles near a paper store, and do not use poisons against pests where children or animals can reach them.
What’s Next
- Learn next: Collection & Preservation — the whole library
- Combine with: The Fragility of Digital Knowledge — the supplement to paper