What size is a pergola main beam? The size of a pergola main beam can vary depending on the design and load-bearing requirements, but common sizes are 4×6, 6×6, or even 8×8 inches. Additionally, local climate and environmental factors can impact the longevity of the wood used in the beams. Please note that these spans are general guidelines, and it’s essential to consult with a structural engineer or local building codes for precise calculations and to ensure the pergola’s structural integrity and safety. Keep in mind that these are approximate spans, and the actual span may vary depending on factors such as the wood’s grade, load, and local building codes.

Here’s a table summarizing typical pergola beam spans for various beam sizes and wood species.