curbell plastics out of aurora ..... its called king starboard .... uv stable marine grade hdpe .... prices have skyrocketed from when i originally priced it out.... cuts drills and routers just like wood ..... used a caulk rope on the frame and screwed hdpe to frame with size 10 self tappers..... if by chance they do not hold up i have rivnuts and 1/4 20 screws to hold it all together ....but i think it will be fine .. 3/4 inch for the floor and 1/2 inch every where else
..matt