I have some HDPE for a backyard setup im in the process of building and i was wondering if the boxes with HDPE need to have some sort of siding like at parks or not. Any advice would help.
no they do not, it really mostly for look and safety (its not fun catching your ski on the supports). As long as you keep a couple 2x4 or whatever youre using on the sides for stability, you should be fine.
its possible to get your leg cought in there and fuck up your knee or somthin, and its a pain in the ass when you ski goes under thur and ejects instead of just tapping it on the side.