Drywall is a tempting material for a porch ceiling: after all, it’s widely available, usually easy to install, and affordable. But I wouldn’t recommend drywall even for inexpensive porch ceiling ideas. The problem is that drywall is susceptible to moisture and thus decay. But the problems don’t end there: even moisture-resistant drywall, also known as MR drywall, will eventually deteriorate. Simply put, drywall of all kinds shouldn’t be directly exposed to humidity and precipitation. Luckily, there are many other affordable material options available.