In this video I review everything you need to know about multiwall (sometimes called twinwall) structured sheet plastic. I review the cost, manufacturers (Polygal, Verolite, Thermoclear, Palram, Sunlite), light transmission, thermal properties, installation details, size, color, shapes and possible uses. As with all of my videos I review the material from the standpoint of an architect evaluating the product for potential use in home design and construction projects.