A ‘footprint’ or ‘ground sheet’ is a piece of material that provides a barrier between your tent or sleeping matt and the ground below. This barrier performs a number of functions including:
Protection against sharp rocks and plants to minimise damage to the tent floor and prolong the life of the tent
If cowboy camping, it provides protection against sharp rocks and plants to minimise damage to your sleeping matt
It acts as a moisture barrier to help keep you and your equipment from absorbing moisture from the ground below
It helps to keep your equipment clean by providing a barrier from the ground below
In addition, sits part of the ‘tent system’ created by some tent manufacturers create that allows the tent fly and the footprint to be used without the tent inner if protection from bugs isn’t required.