A pergola's roof options are decided not only by the aesthetics of the homeowner but what purpose the pergola is to serve. Pergolas are overhead constructions, originally designed to be covered walkways. Today, pergolas serve as shade bearing focal points around patios, hot tubs, decks and even pools. Typically a pergola is constructed out of wood, which may be finished or left natural, and contains a vine or climbing plant that grows up the sides and across the roof, providing shade and decoration.
Grapevine pergolas are pergolas that have a grapevine trained up the sides and across the roof. This provides shade for a walkway or patio, while simultaneously giving off a sweet smell and delicious treat throughout the latter part of the season. A grapevine pergola requires a rooftop that is sturdy enough to hold the woody vines once they mature, while simultaneously providing openings for grape bunches to hang and ripen. For this purpose, a checkerboard-pattern wood construction is typically used, with two-by-fours providing the overhead trellis.
Wire Roof Pergola
A wire-roof pergola is a great option for one containing a relatively lightweight plant, such as a trellis-growing rose. Typically rosebushes are not as heavy, even at maturity, as a grapevine. Because of the rosebushes relative light weight, heavy-gauge wire can be used to substitute for the two-by-fours in the grapevine pergola. The rose can be tied to the wire and, once it fills out, the wire will all but disappear amongst the flowers and leaves. This makes using a wire roof pergola a great option for an archway-style covered walkway.
A pergola containing a plant that does not require substantial pruning, and does not bear fruit, such as ivy or honeysuckle, can have a solid overhead roof to make a dry space under your pergola. Because of the moisture likely to accumulate under your vines, opting for a corrugated plastic or fibreglass roof is a good option. The ribs in the plastic board will act as gutters, preventing standing water from accumulating in low spots in your roof and harbouring mosquitoes.
Some homeowners like to create a tropical island look with a grass roof. Grass roofs are made with clusters of thick grass, resembling hay. This material can be purchased in most home improvement or craft stores, and typically comes in sheets or rolls. It is installed in such a way that water runs off of the grass, making a dry spot underneath your pergola for a patio set or tiki bar. This is a great option if you are not intending to grow anything on your pergola, as a vine or rose will only serve to displace the grass roof thatch, and make it difficult to change the grass at the end of the season.