Double Beam Pergola

A free-standing timber pergola with a pair of beams sandwiching the posts on each side, crossing rafters and thin top runners. Post, beam, rafter and runner sections, Length, depth and overhang, Rafter and runner spacing, Timber or painted finish

Details

Category: Pergolas › Open and Fixed Roof Pergolas

By Huu Khanh Nguyen · Updated November 5, 2026

Parameters

Name	Default	Unit
Length between posts	4267.2	mm
Depth between posts	3048	mm
Overhang	304.8	mm
Post section	152.4	mm
Post length	2438.4	mm
Beam depth	203.2	mm
Beam thickness	50.8	mm
Rafter depth	152.4	mm
Rafter width	50.8	mm
Rafter spacing	406.4	mm
Runner section	50.8	mm
Runner spacing	406.4	mm
Beam and rafter ends	scroll
Return beams	true
Corner braces	true
Timber	timberStainCedarRed
Post base	true
Lower base projection	38.1	mm
Lower base height	203.2	mm
Upper base projection	25.4	mm
Upper base height	203.2	mm
Overall length	spanX + 2 * overhang	mm
Overall depth	spanY + 2 * beamThickness + 2 * overhang	mm
Overall height	postLength + rafterDepth + runnerSize	mm
Posts per line	Math.ceil(spanX / (beamDepth >= 203.2 ? 6705.6 : 4876.8)) + 1
Rafter count	Math.floor((sizeX - rafterWidth) / rafterSpacing) + 1
Runner count	Math.floor((sizeY - runnerSize) / runnerSpacing) + 1