A 4/12 pitch to the roof and a 14-foot eave height has improved air flow in this free-stall barn. The previous roof was less steep, and eave heights on the ends of the barn were only 10 to 11 feet. “We have noticed a big diffference,” says co-owner John Silva, of Denair, Calif. “Cows are more comfortable. It’s a lot cooler inside,” he says. A 4/12 pitch is equivalent to an 18-degree slope. For every 12 horizontal inches, the roof rises 4 vertical inches.