A pergola is a decorative shade structure. Pergolas are often used to connect buildings, similar to a breezeway but without full cover from the elements. They are also found as freestanding garden follies, providing a focal point to terminate a vista or a quiet corner for reflection. Perhaps most commonly, they are erected as an extension of a home similar to a covered porch.

Four parts of a pergola

Traditional pergolas have four primary building blocks: the columns, or elements of support; the beams, or spanning elements; the rafter tails, or shading elements; and the purlins, which link the rafters together (and create still more shade). Within the various uses for a pergola and through the many possible variations of the building blocks, you will find endless opportunities when designing a traditional pergola.

Column and beam alignment

When using tapered round columns, the alignment of the neck of the column with the beam above is a critical detail to get right. The common mistake is insetting the column under a beam that is too big. You can either set the beam width to match the neck of the column, aligned front and back, or set it smaller than the neck and center the beam on the column.

Column-spacing options

How you choose to space the columns will largely depend on the application, as well as the column height, the scale of elements, and the length and width of the pergola. When the pergola is freestanding or connecting two buildings for longer distances, the column spacing will be similar to the column spacing for an arcade, where you typically want the distance between the columns to be no greater than the height of the columns, but ideally not less than the width of a golden rectangle.

If the pergola is linking…