Rafter And Slat Pergola

A free-standing timber pergola on posts with two headers, crossing rafters, a layer of shade slats on top and optional knee braces.

Details

Category: Pergolas › Open and Fixed Roof Pergolas

By Huu Khanh Nguyen · Updated November 5, 2026

Parameters

Name	Default	Unit
Width between posts	3657.6	mm
Depth between posts	3657.6	mm
Overhang	406.4	mm
Post length	2438.4	mm
Timber stack	heavy
Timber	timberStainCedarRed
Post base	true
Lower base projection	86.4	mm
Lower base height	101.6	mm
Upper base projection	58.4	mm
Upper base height	101.6	mm
Brace length	609.6	mm
Brace depth	101.6	mm
Overall width	spanX + 2 * overhang	mm
Overall depth	spanY + 2 * overhang	mm
Overall height	postLength + headerHeight + rafterHeight + slatThickness	mm
Header height	[203.2, 203.2, 254, 304.8, 304.8, 304.8, 304.8][seriesIndex]	mm
Rafter spacing on centre	[609.6, 609.6, 609.6, 609.6, 609.6, 609.6, 457.2][seriesIndex]	mm
Slat spacing on centre	[304.8, 304.8, 304.8, 304.8, 304.8, 304.8, 254][seriesIndex]	mm
Post section	[152.4, 203.2, 152.4, 203.2, 254, 304.8, 203.2][seriesIndex]	mm
Header width	[152.4, 203.2, 76.2, 101.6, 152.4, 203.2, 101.6][seriesIndex]	mm
Rafter width	[50.8, 101.6, 76.2, 76.2, 101.6, 152.4, 76.2][seriesIndex]	mm
Rafter height	[152.4, 203.2, 203.2, 254, 254, 203.2, 254][seriesIndex]	mm
Slat width	[50.8, 76.2, 101.6, 152.4, 152.4, 152.4, 152.4][seriesIndex]	mm
Slat thickness	[50.8, 76.2, 50.8, 50.8, 76.2, 101.6, 50.8][seriesIndex]	mm
Rafter count	Math.floor((sizeX - rafterWidth) / rafterGrid) + 1
Slat count	Math.floor((sizeY - slatWidth) / slatGrid) + 1
Posts per header line	spanX > 6096 ? 3 : 2
Brace thickness	[101.6, 101.6, 50.8, 76.2, 101.6, 152.4, 76.2][seriesIndex]	mm
Series row	['light', 'heavy', 'sawnSmall', 'sawnMedium', 'sawnLarge', 'sawnExtraLarge', 'timber8000'].indexOf(series)