Sgt. Rock I do not know how to tell if it is coated or impregnated. My guess is coated. One side is shinier. I just felt the material in walmart and they don't even tell you what it is. It felt waterproof so I bought the whole roll. Eventually I tied some water in a bag of it and hung it overnight and none leaked and I thought, wow what a deal.
I did lower the tarp closer to the ridgeline and I'm sure it will give pretty good coverage. The ridgeline is 132 inches before the hems and the hammock ridgeline is 103, I think. That will give me over a foot on each end. The tarp is only 3 inches wide near the ends though. Next I will make another 11 x 10 that I can tie out with doors.