I looked into building a GH with polycarbonate panels before I decided on film instead. The panels being the majority of the expense, I was laying out the size based on the length of panels/ least waste possible.
So long story short you don't want a 7' side wall that you waste 1' of panel from every one. I believe I was planning to use sheet metal from the ground to only need half of a poly panel for each (4' wide) wall section.
I think I found what I considered decent prices on the poly panels at a local Menards. The online prices were just too much with shipping.
