I want to enclose a porch, but I am unsure of the proper material to use. I need something 1/2" or 7/16" thick, and would like 4'x8' sheets preferably. I was looking at a 50 year siding that is used in the construction of sheds, and sells for about $25 per sheet, but I would also like to get other ideas. The material will be used as the exterior walls of the porch, so something that has good water resistance is what I am looking for. Low cost, easy installation are important. I'll bet there are many hams that are contractors, or have construction experience, so please throw some ideas at me.