When I had to cut the bottom coraplast material on my 5th wheel, I cut a 3 sided flap. Large enough for me to fit up and into the bottom for the repairs I needed to do. Folding the cut flap down. I cut the flap so should it ever come loose while driving the opening was cut towards the rear facing position. This way the wind could notcatch the flap and pull it open while under way. To secure the flap when I was done, I stopped at Home Depot and bought a 1 inch wide by about 1/2 inch thick strip of wood. I cut the wood long enough to fit the cut sides of the coraplast. I then overlapped the wood so 1/2 inch was laying ontop of the uncut edge, letting me use wood screws to screw through the plastic material into the wood. After doing all three sides the same way, I then lifted the cut flap up and then used the same type of screws to secure the loose flap to the exposed wood edge. Its secure, and sealed. I then used the Gorilla tape to keep dirt/water from entering the bottom. Should I ever need to gain entry again, pull the tape and unscrew the flap. Over the years the tape would start to pull loose, but the flap never moved.
