Hey @dandurston I want to make a polycro sheet for the tent what are the dimensions of the tent? I couldn't figure out from the description (I guess it's just me perhaps I didn't looked in the right place)
DorkafriI think a groundsheet isn't needed for normal use, but it good if you're camping on bare rock, gravel or have no patience to check a site for sharp rock and sticks before pitching.
If you want to add one, I recommend ensuring that it doesn't stick out from under the tent at all, or else rain will land on it and run under the tent where it gets trapped between the groundsheet and the floor. So I would cut a piece of material the same shape as the floor and then tie or clip it to the cords at the four corners of the floor so it stays in place and doesn't peek out.
Here is a diagram that should show the numbers you need:
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Both ends of the tent are the same but I've just shown the detail at one. I would start by cutting a piece of plastic that is 96.5" long and 28" wide, and then you can snip the opposite corners off of that to make it into the parallelogram shape.
dandurstonI tried this with some Polycro cut per Dan's dimensions plus a little extra (1/2") to "hem" the cut edges with the double sided tape that comes with the window kit. Then reinforced each corner with a bit of Leukotape, a small washer and a bit of cordage to connect to the inner tent corner cord stays. Weight is 53g. Looks good, but we'll see how it works in the real world.
mejbp...a little update. I have used this footprint configuration for about 30 nights. So far it is holding up and the only sign of wear is the tape and polycro are a little dirty now.