Custom Ground Cloth/Tarp (how to cut)

Posted by: Spherical Cow

Custom Ground Cloth/Tarp (how to cut) - 05/29/12 12:14 PM

Not sure how widely known this technique is, but a friend suggested it... I got great results. This technique applies to plastic tarps. Here goes:

How to cut a custom ground cloth/tarp:
-I opted for a 5Mil thick tarp available at your local hardware store for ~ $15... the one in the photo is 8x10 ft.
-The tent I have is the TarpTent Moment (pic1, pic2).
-Trace out the shape you need (I placed the tent on the tarp, made some marks, then connected the dots using a straight edge... making sure everything was nice and symmetric).
-Now you are ready to cut (a flat smooth concrete garage floor is ideal for this task)...
-Use a standard soldering iron set pretty high (mine was set to 800F, nearly max setting)... place a straight edge (metal ruler OR similar) and trace your lines. Do a few practice cuts on scrap to get the hang of how fast you should go.
-Tracing with the iron cuts / melts the plastic tarp... preventing the fraying that would occur if simply cutting with a blade.
-Take your time and you'll have a nice custom shaped ground tarp. I was lucky enough to be able to utilize two of the grommets that came on the tarp.

Tarp as purchased:


Example cut with iron:


Tarp after cutting:


Tarp in (small) stuff sack (w/ 4 MSR groundhog stakes and guy-line):
(large stuff sack is tent; foot is for scale grin )


Posted by: PerryMK

Re: Custom Ground Cloth/Tarp (how to cut) - 05/29/12 01:38 PM

I use a Hefty Lawn bag. It's designed not to be punctured readily, is waterproof and very light.

I'm not sure I can take advice from you; your shop is way too clean. Even your workbench is organized. Just kidding! smile

I like the grommet usage.
Posted by: OregonMouse

Re: Custom Ground Cloth/Tarp (how to cut) - 05/29/12 01:54 PM

You want to cut the footprint about 2 inches less on each side than the perimeter of the tent. Otherwise rain going down the sides of the tent will run right under the tent on top of the footprint.

How much does your footprint weigh?

Most people use either Tyvek or polycro (the kind of plastic used in storm window kits). I haven't used a footprint/ground cloth in years. Silnylon floors are amazingly durable.
Posted by: lori

Re: Custom Ground Cloth/Tarp (how to cut) - 05/29/12 03:27 PM

Originally Posted By OregonMouse


Most people use either Tyvek or polypro (the kind of plastic used in storm window kits). I haven't used a footprint/ground cloth in years. Silnylon floors are amazingly durable.


I think you mean polycryo.

I use tyvek, or nothing at all.
Posted by: Spherical Cow

Re: Custom Ground Cloth/Tarp (how to cut) - 05/29/12 03:27 PM

I did cut the ground tarp just a bit smaller than the perimeter of the tent (I assumed this to be common knowledge)... I'm new to this forum, not camping wink

I didn't weigh it yet... I will and post weight. I first used 1Mil plastic sheet I had lying around, which weighed 'nothing', but after a few nights on the trail I decided it was just too thin. I paid a lot for my tent, and don't want to puncture the floor (which seems precariously thin on the Moment). The extra weight of a 5Mil plastic sheet is worth it, IMHO. It may very well be overkill.

A special note: For the Moment, you want to cut your ground cloth so that it's just a bit smaller than the perimeter of the tent, not simply the size of the bathtub floor. This prevents ground moisture from evaporating and rising up through the mesh of the Moment that faces the ground (and the vestibule area, too). This GREATLY reduces condensation problems. << This is another reason to use the ground tarp with the Moment.
Posted by: OregonMouse

Re: Custom Ground Cloth/Tarp (how to cut) - 05/29/12 04:09 PM

Since we do have a lot of beginners visit this forum, it is a good idea to write instructions for them, which is why I mentioned cutting the footprint smaller.

Silnylon appears fragile but is amazingly tough. I've never used a ground sheet with it and never had any kind of puncture, even with my dog sleeping inside.

However, I'm intrigued by the idea that the footprint might reduce internal condensation!
Posted by: Spherical Cow

Re: Custom Ground Cloth/Tarp (how to cut) - 05/29/12 07:12 PM

Understood. I didn't realize the silnylon was so tough.

If you see no need for the ground tarp for protection, then thin (e.g. 1MIL) plastic should serve well to reduce condensation (if your tent has netting facing the ground, or a large vestibule, like mine). In fact, the plastic sheeting shown in the pics of my tent is 1MIL that I originally cut to fit. I may end up going back to it, in light of your input!

BTW, the 5MIL tarp weighed in at a hefty 9oz! I suspect that is WAY too much for most of you weight-conscious. I didn't realize it would weigh that much. Oh well. Thanks for the input.
Posted by: Franco

Re: Custom Ground Cloth/Tarp (how to cut) - 06/05/12 12:27 AM

good idea about covering the vestibule area too.
yes that does reduce condensation from ground evaporation.
(one can always fold the vestibule bit under the floor if not wanted ..)

Yes it is Polycryo , as far as I know just a name that GG made up for their window insulation material, but most do call it polycro anyway..
Franco