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Do You Need a Ground Sheet for a Bivy?

Bivy sacks are a popular choice among hikers and backpackers because they offer protection from the elements without the extra weight of a tent. But do you need to use a ground sheet with your bivy sack? In this blog post, we’ll explore the pros and cons of using a ground sheet with your bivy sack and help you decide if it’s right for you.

Bivy sacks are designed to be an extremely lightweight option for one-season sleeping. They’re ideal for backpacking, hiking, ultralight camping, or any other situation where you want protection from the elements without the extra weight of a tent.

They usually have waterproof shells and they can be completely enclosed or open at the bottom so you can use them in warmer weather when you don’t need to worry about bugs, rain or snow.

Ground sheets

Ground sheets are generally made out of plastic or polyethylene for waterproof protection. Some models offer floorless designs that allow you to lay directly on the ground with no barrier between your sleeping bag and the dirt.

These kinds of bivy sacks do not require a ground sheet because there is nothing exposed that would need extra protection from moisture when rain hits the surface above (i.e., leaves, twigs, logs).

However, some bivy sacks include an insulated top cover in addition to an eVent breathable base. These kinds of bivy sacks require a ground sheet under them because the breathable material is on both sides of the shelter, allowing moisture to pass through from either side.

If you used it without a ground sheet and there was condensation on your sleeping bag when you woke up, that would defeat the purpose of both the waterproof shell and the breathable base.

Many hikers and backpackers don’t use a separate ground sheet with their bivy sack for this reason:

Using a ground sheet can increase weight and bulk.

Most people don’t see the added weight of a ground sheet worthwhile unless they plan to use their bivy sacks in very wet conditions.

However, if you’ve spent any amount of time sleeping on the ground, whether camping or working outdoors, you know that there are many other benefits to using one: It protects your sleeping bag and clothes from dirt and debris.

This is especially helpful during spring and summer when bugs are out in full force.

Insertion and removal of your sleeping bag (or quilt) is easier

However, if you happen to be camping on an established site where the ground has already been cleared of sticks and rocks, you may want to avoid getting a ground sheet because it could make it more difficult for you to find that perfect place for your tarp or tent

If you’re using a bivy sack/ground sheet combination with no tarp or tent protection overhead, they should be positioned under trees or overhanging brush so rain doesn’t drip down onto them.

Finally, some people argue that using a ground sheet can reduce airflow slightly through the bottom of the bivy sack so condensation occurs inside instead of outside.

Alternatives to using a Ground sheet

In general, most hikers and backpackers choose to not use a ground sheet with their bivy sacks whenever possible.

This is why they make double-walled bivy sacks that have a breathable base but a waterproof top. These bivy sacks can be flipped around so the breathable material is on the bottom for warmer weather and more airflow.

They’re lightweight and more discreet than classic tent models. If you want an easy way of blocking out bugs or extra protection from dirt or sand, consider using a mesh bug screen or sand fly net.u.

In general, most hikers and backpackers choose to not use a ground sheet with their bivy sacks whenever possible.

This is why they make double-walled bivy sacks that have a breathable base but a waterproof top. These bivy sacks can be flipped around so the breathable material is on the bottom for warmer weather and more airflow.

They’re lightweight and more discreet than classic tent models.

As an alternative, you can consider using an ultralight tarp instead of opening up your bivy sack completely. This will keep you shielded from rain and wind without trapping in a lot of heat.