This is something I've wondered about for years so finally I'm asking. Why do people use purchased footprints for their tents? Or make them from Tyvek or other special fabrics?
My understanding of the footprint is it helps prevent tent wear by preventing the tent floor rubbing in the dirt when one is in the tent, preventing water from soaking through, and preventing minor twigs or pebbles from poking through.
I've always used a Hefty Lawn bag cut down the sides and folded open lengthwise. It's big enough to cover the area of the tent that I will be putting weight on, is waterproof, and being a lawn bag is puncture resistant. Plus they're cheap. If it sticks out from the tent, I shove it under the tent. I see no particular advantage for it to match the tent perfectly; it just needs to protect the area of wear.
I have no idea what it weighs but it isn't much. One bag can be re-used many times, probably as many as most fabrics.
Am I missing something? I know, do whatever you want, HYOH, etc. But is there an advantage to Tyvek or custom footprints?
I think the manufacturer's footprints are just a time-and-trouble saver, and of course they add some profit margin.
Tyvek doesn't seem it has any advantages. It's fairly puncture-resistant, but not really waterproof. I tried it once, and it seemed to pick up lots of dirt and moisture, when compared to polyethylene sheeting.
In Beyond Backpacking, Ray Jardine says, "I think the interest in this material is based more on the name, which has sort of a fresh, exotic appeal to those unfamiliar with it."
2- or 3-mil poly sheeting seems the best. I like it to be big enough to use as a separate ground sheet...not sure if the Lawn & Leaf bag is big enough.
Always remember that you are absolutely unique, just like everybody else. -Margaret Mead
Loc: Portland, OR
The only advantage I can see to the pricey commercially designed footprints over the garbage bag setup you described would be you'd throw away less plastic by using one.
I get around the problem by spending as much time as needed to pick-and-toss aside the small twigs, fir cones and small rocks that could puncture my tent floor. That way I don't need any footprint at all. I never take the shortcut of sweeping the whole tent site down to bare earth, because that's hardly a Leave No Trace practice. I leave the harmless duff in place.
"The factory footprints are handy because they lock into place"
I use heavy duty window film as a groundsheet. Same piece for a couple of years now. I also put some gorilla tape in each corner, then added a grommet to each small square of tape, so I can lock it in place if desired, though the main reason I added the grommets is so I can lay the sheet out in wind without it blowing away.