Let's talk about different types of shelter.
Shelter - This is often one of the biggest expense (though it doesn't have to be that way) involved in backpacking. It can also be one of the heaviest things you carry, though it doesn't have to be that either. Shelter is just a broad term that refers to what keeps us dry, protected from the wind, protected from insects, and protected from moisture. Most people automatically think of tents when they think of shelter. We will address tents, tarps, and bivies.
Tents - Backpacking tents are focused on being lighter weight than camping tents. Tents can be separated into lots of categories that aren't necessarily mutually exclusive.
- 3 season tents - this means they are suitable for use in spring, summer and fall. The inner portion of the tent has a waterproof floor (at least it should be) and mesh on the sides and top. A waterproof (hopefully - or at least if you buy a quality tent) rain fly goes over the top to keep precipitation out. These are the most common tents and will likely be what you see at stores.
- 4 season tents - made for use in winter, heavier because they are designed to handle a foot or more of snow sitting on top of them so they have more poles and stronger poles, inner tent often has panels that zip over any mesh to increase warmth. This microadventure and this other microadventure show the 4-season tent I use.
- Freestanding tents - this means they don't require stakes to make them stand up the right way. Not staking a tent is a good way to turn it into a several hundred dollar kite, so they still get staked or anchored in some ways. The advantage is if you are camping on rock (think Moab, Utah) your tent will still stand up. Freestanding tents typically weigh more than non-free standing tents. Even though a tent may be marketed as freestanding, it is very likely that the rain fly will have to be staked out to function properly.
- Non-freestanding tents - just means you must stake them out to create the structure the tent designer intended. They are typically light and pack down very small.
- Double wall - most tents you have seen probably fit this category. There is the inner part of the tent and the outer part (i.e., often called the rain fly). Double wall tents are heavier than single wall tents, as you would suspect.
- Single wall - just what the name implies - there is only one piece of fabric between you and the outside. Lighter than double wall, but more prone to condensation issues. An example of condensation is when you breathe on a mirror and it fogs up. Water vapor from your breath or perspiration condenses on a surface. You wake up and think your tent leaked even though it may not have rained at all. You are really just seeing moisture that collected from the inside, not the outside. (You will still get condensation in double wall tents, it usually just condenses on the rain fly.)
Tarps - This is my personal favorite. There is no floor. There is just a piece of waterproof fabric over your head and on the sides to some extent. This is way lighter than a tent (tarp alone can be as little as about 6 ounces which is about as much weight as 3/4 cup of water). Advantages = lightweight, you can see outside easily, you can walk under it with your shoes on, you can sit in it while it rains and comfortably watch outside, you are more connected with nature (sounds kind of cheesy, but is true - there are no real barriers, you are right there, not walling yourself off). Also, many are designed to be used with trekking poles, which means you get dual use out of your equipment and don't have to carry the weight of poles. Disadvantages = you will need other protection for insects if it is mosquito season, you will need to put a piece of plastic (or bivy, which is what I use) on the ground under your sleeping system, it will be a bit breezier inside if it is windy, and you need to have more skills and confidence to safely and happily use these than a tent. Some backpackers sleep in hammocks with a tarp over top.
Bivies - Think of a bivy as a big floppy sock that goes over/around your sleeping bag. Some are made to be fully waterproof and essentially are like mini tents (can't even sit up in it). I'm not a fan of these since they can weigh as much as a small tent or more and condensation can be a bigger problem. Others are made to pair with a tarp and have a waterproof floor and bug netting on top to keep water and bugs out. This is what I use with my tarps when I need bug protection. They weigh about 6 to 8 ounces. The photos above and below show examples of bivies under a tarp.
Example - This microadventure is from a hike in Idaho to a lake with an airplane that crashed during World War II. There is a pretty cool story about how all the crew managed to survive and how some hiked out for about 40 miles in the snow living on squirrels to bring help to their injured buddies. Anyway, my trip was a very, very wet trip with lots of rain. The tarp system I used worked great. A tarp or tent that hadn't been checked for being waterproof would have made for a very miserable experience. [Hint, hint - test your system out thoroughly before depending on it to keep you dry and protected.]
