How to Avoid Moisture in a Bivy Sack

How to Avoid Moisture in a Bivy SackIf you prefer a fast and light approach to backpacking or mountaineering, then using a bivy sack is the way to go. A bivy sack is much lighter than carrying an entire tent, often requires no poles for setup and packs to a much smaller size. When bivouacking however, due to the small space of a bivy sack, you are more likely to collect condensation and moisture inside the bivy. There are a few things that you can do to help prevent and minimize the moisture.


Difficulty: Moderately Easy

Things You’ll Need:
  • Bivy sack with no-see-um mesh netting
Step 1
Purchase a bivy sack that has fine mesh netting, such as no-see-um netting. Many are designed this way, enabling you to keep a portion of the waterproof laminate shell open while still keeping any insects from getting inside. This really helps to ventilate as well in the warmer months.
Step 2
Leave a small opening in the zipper of your bivy even if it is winter. The air you breathe out in your bivy has moisture in it, and if it is not allowed to escape out an opening will condense on the outside, leaving your sleeping bag damp in the morning.
Step 3
Try to sleep with your face towards the opening in the zipper of the bivy if all you have left open is a small hole. Wear a hat to sleep. If it is extremely cold, only leave open a tiny opening right at your mouth and try not to shift around too much.
Step 4
Try to start the night with a dry bivy. If your bivy was damp from the night, before then try to dry out the inside by turning it inside out and laying it out on a dry day.
Step 5
Don't worry too much about the outside of a bivy sack. The outside should be waterproof or at the least water-resistant. Try to purchase a bivy sack that is made with a waterproof but also breathable material, such as Bibler's ToddTex laminate.

Article Written By Naomi Judd

Naomi M. Judd is a naturalist, artist and writer. Her work has been published in various literary journals, newspapers and websites. Judd holds a self-designed Bachelor of Arts in adventure writing from Plymouth State University and is earning a Master of Fine Arts in creative writing from the University of Southern Maine.

Don't Miss a Thing!

All our latest outdoor content delivered to your inbox once a week.



We promise to keep your email address safe and secure.