Our eight-foot by eight-foot pergola kit has vertical full-dimension 4" X 4 " columns that are nine feet long. Please see Assembly Instructions for greater detail. If you require longer or shorter posts just let us know.
The sizes listed for our pergolas are the roof dimensions. For example, a 15' X 15' pergola kit has a roof top layer of 2 X 2's that are 15 feet long and the rafters below it are also 15 feet long. Both the rafters and the roof top layer timbers are spaced eighteen inches apart on center. The posts are normally 12 inches set in from the roof edges. In other words, a pergola kit listed as 15' X 15' has the posts at 13' X 13' (exterior dimensions). The columns are spaced twelve feet, two inches by twelve feet, two inches apart (inside dimensions).
All pergolas are built with extensive use of notching for beauty and structural strength. Each roof support timber is notched into both of its posts. Then each rafter is notched at four points into both its roof support timbers below it. Finally, each 2 x 2 roof timber is notched into every rafter below it to create an interlocking "web" that is structurally strong and attractive.
The pergola roof has 3 levels. The top level is either the lattice panels or the 2 X 2 timbers depending on your roof choice. Below the top level is the roof rafters (either 2 X 4's or 2 X 6's depending on the size of your pergola). The roof rafters are also spaced eighteen inches apart on center. If you would like more shading, we can add more rafters and 2 X 2's. The lowest level of the roof is the roof support timbers. The roof support timbers are perpendicular to the roof rafters above them and they create the two sides of the pergola that have 4" to 6" less clearance (depending on the size of the pergola) when you walk underneath the set.
The two sides that have the roof supports are usually considered the "sides" of the pergola, while the other two sides with taller head space are considered the entry and exit sides. Please specify when ordering a rectangular shaped pergola whether you prefer your roof supports on either the short length of your set or the long length.
All pergolas up to and including the ten foot by ten foot kits are normally built with full-dimension 4 X 4 columns and full-dimension 2 X 4 roof supports and roof rafters. All pergolas above the 10 X 10 foot kit are made with full-dimension 5 1/2" X 5 1/2" columns and full-dimension 2 X 6 roof supports and roof rafters. If you're ordering a small pergola and you would like the fatter timbers, just let us know. We can custom make any size pergola you like. Pergola kits over 20 X 20 require additional posts. |