The first rain awning lasted about a year, possibly the life span one can expect from an awning home-made inexpensively out of plastic dropsheets and duct tape. It did not survive being taken down for the removal of that awful galvanized gutter; the duct tape peeled loose a bit and then restuck to whatever was nearby. When I tried to unfurl it again, the plastic tore in several places.
I constructed a new one over several days in early May, first rigging together the rope harness to support it and then cutting sheet plastic to size and sealing it to the ropes. I used color-coded ropes to make unfurling and lofting it easier: red on one side, green on the other side, blue down the middle, white across from one side to the other. Nancy helped with the sealing and with lofting the awning into place.
Last year’s awning was made out of the lightest plastic available (6mil as I recall), since it seemed at the time that a lighter awning would last longer. This year’s was made out of the heaviest I could find, 20mil.
I tried silicone sealer this time since the onstruction-grade duct tape had started to come loose after a year, and once it came loose it would stick to any part of the awning it came into contact with, often causing a tear. A small test indicated the sealer would adhere to the plastic. I had to patch a few places where the sealer pulled free later using (of course) duct tape.
So far it seems to be working. Some readjustment was needed to keep that corner as the lowest spot, to keep water from collecting in another spot where the accumulating weight could tear the awning apart.