Square pressure-treated poles around the perimeter provide unobstructed interior space. Roof purlins and wall girts are built to withstand heavy snow and wind loads. Many different colors of special order steel siding are available. Check with your local store for actual color samples, as colors can vary by market. Use a different color trim for an attractive two-tone building. Farmland packages include Galvanized Corrugrated iron, which is generally used only when appearance and durability are not a factor. It is much less expensive, but covered by no warranty. Most of our locations keep 1-1/4" or 2-1/2" corrugated iron in stock for immediate purchase. Popularity in the region is usually the main difference, and one size has no benefit over the other.