Concrete footing or pile driven options. Less Steel, Equal Strength. No Welding. 10"dia. x 4' Post Footing. Concrete footing ideal for high acidity soil. Modified Purlin Does BOTH! Narrower Footprint. Panels Slide On In Seconds! All Components Pre-Punched. Slotted holes in super-pulin allow for angle adjustment. 5° - 30° Tilt Available. All Galvanized Framework.