Tell us about yourself!
IBCs, I believe, are made of HDPE. In my experience welding HDPE only works where flexing is negligible. The welds are more brittle than the surrounding material and crack over time. On the other hand, EDPM pond liner is very adaptable to different shapes, but one would need to fully support the sides for the static hydraulic load and the live load (people).
Two thumbs up here! I'm going to show it to my friends with a cabin up in the mountains!
I liked the design. I wonder if it could be adapted to a 2-axis plotter/mill for cleaner cuts? What is your maximum working depth?