MY FIL and BIL built a fairly large equipment storage shed about 15 years ago and it served them well over the years until it got struck by lightening during a bad storm last spring and burned to the ground. It was protected with a state approved lightening protection design and installed by a licensed electrician. They lost 7 tractors from 30 to 100 HP that were used daily on their 750 acre farm, a 3 year old large round baler, a mower/conditioner, an 8 ft King Kutter rotary tiller, a 15 ft bat wing brush hog, 2 hydraulic grader blades, the old square baler, 2 tons of horse feed. 15 rolls of woven wire fencing with 250 metal stakes, and a 1,000 gal diesel fuel tank with pump. A devastating loss with only partial insurance coverage. I do not know how they could have provided a better storage unless they went with a total masonry system.