Traditional pergolas are normally built out of wood. The most common types of wood used include pressure-treated pine, cedar, redwood, and teak. A wooden pergola does require staining and sealing annually to maintain it. Over the past few years, many people have switched to using aluminum and vinyl to build pergolas as these materials stand up to harsh weather better. Some of these composite materials will even make a pergola virtually maintenance-free and are also not susceptible to insect damage or rot.