Gresham Pergola Dec, 2016. Call Portland Roof and Deck for all your roofing and decking needs. 503.465.4940.A Pergola is a structure that is usually made out of cedar. The main purpose of a pergola is shade and the “art look” of the structure. They do not provide any rain protection like a roof. We have built multiple designs from the basic look to custom designer large lumber Pergolas.The design is based on what you want the pergola to look like. The size of the lumber can be as large as you like. The Lumber just needs to be large enough to carry the span. We pre-stain all the lumber before we build the structure.The Pergola below has a 12′ span and we are using paired Cedar 2×8, Paired Cedar 2×10 header and cedar 2×4’s across the top of the structure.We can also build custom large timber pergolas.Gresham Pergola, Give us a call fro a free estimate.Portland Roof and Deck.firstname.lastname@example.org.