Polycarbonate sheets are available in two different forms. There’s multiwall polycarbonate, a structured sheet with hollow air chambers; and solid polycarbonate, a clear, flat sheeting that looks like glass. There’s no difference in the quality of either version. Each has its own distinct advantage, so the final decision on which one to choose depends on your project and its esthetics. We should alert you, however, that if you’re a fan of glass, you need to know that polycarbonate has advantages that traditional glass can’t duplicate. But more on that later.