UKC

I'm about to make one of these but wondered if they needed to be fixed to the tent or whether just laying it under the groundsheet would do? Obviously the former needs a bit more work such as eyelets to fix it to pegs.

Ta.

Well. The better it stays put, the more protection offers. 

I would try to DIY some cord loops through which the pegs go. Fastening by some sticthing and glue. 

I'd be worried about it blowing away, before you'd had a chance to pitch the tent on top. You can buy those snap on eyelets fairly cheaply, just fold the corners for strength. 

I've made them.  I always put grommets in the four corners, and install thin rope loops in the grommets that you can put the tent corner stakes through (so you aren't using any extra stakes).  If it is windy you can stake out the footprint first and then lift and replace each stake through the corresponding tent corner.

Make sure to trim the tyvek to an outline slightly smaller than the tent, otherwise it will channel water under the floor.

I think the corners need to be reinforced so the grommets don't tear out.  I used duct tape for that.

Thanks, think I'm going to go for grommets and attach them semi permanently to the corners of the groundsheet. This seems a bit more logical than pegging it out given the design of my tent.