Waterproof Backpack

Waterproof backpacks, a phrase that covers two different things

A waterproof backpack can mean a sealed roll-top sack that survives being dropped in a river, or a coated rucksack that shrugs off a downpour and keeps a laptop dry on the walk to the office. The range holds both, from 25 and 30 litre daypacks through 40 and 50 litre loads, with tactical laptop carriers, survival packs and dry bag styles among them. Knowing which of the two definitions applies to a given pack is the whole decision.

Water resistant or genuinely sealed?

A water resistant pack uses a coated fabric and a storm flap, and it leaks eventually through the zips, the seams and the wet patch that forms where the back panel presses against a jacket. A sealed pack uses welded seams and a roll closure, has no zip into the main body, and keeps water out even when submerged. Neither is right for everything: a sealed pack has fewer pockets and no quick access, while a resistant pack organises kit far better. For paddling, coasteering or a boat, the honest solution is a coated rucksack with the contents inside a drybag.

Does a roll-top actually seal?

It does, and only when it is rolled properly. The top of the sack has to be squeezed flat, folded over on itself at least three times, and clipped so the fold is held under tension. One or two rolls leave a channel that water tracks along, which is the usual reason someone concludes a sealed pack does not work.

Which capacity for which day?

• 25 to 30 litres: a day on the hill or a commute, holding waterproofs, lunch, a flask and a laptop sleeve.
• 40 litres: a long day in winter, or an overnight in a hut where bedding is provided and only clothing travels.
• 50 litres: camping loads with a sleeping bag and a mat, or a family day where one adult carries for several people.
• Back length over litres: a pack that does not match the torso will hurt at any capacity, so check the back system before the volume.

How does a sealed pack breathe against the back?

Poorly, and it is the trade nobody mentions. Welded fabric cannot pass sweat vapour, so the shirt under a fully sealed pack ends up damp from the inside on a warm climb. Some packs answer this with a suspended mesh panel that holds the sack a finger's width off the spine, letting air move behind it. Others use ridged foam channels, which help less but weigh less too. If the pack is mainly for warm-weather walking, this detail matters more than the coating, and a ventilated coated pack from the wider military backpack selection may serve better than a sealed one.

How is the finish looked after?

Rinse salt and grit off after coastal or muddy trips, since abrasive particles are what wear a coating off the fabric from the outside. Dry the pack open and upside down, never rolled and stored damp, because the inside of a sealed sack is where mildew starts. Larger framed loads for multi-day carries are gathered under bergen backpack. Smaller sacks, holdalls and pouches built the same way sit under waterproof bags.