Free-Standing Gable Patio Roof
A free-standing double-slope roof with a ridge beam, paired sloping rafters, purlins and corrugated roofing on square steel columns.
Details
Category: Pergolas › Open and Fixed Roof Pergolas
By Huu Khanh Nguyen · Updated November 5, 2026
Parameters
| Name | Default | Unit |
|---|---|---|
| Roofing panels along the ridge | 6 | |
| Gable width | 4200 | mm |
| Column height | 2400 | mm |
| Purlin spacing | 1200 | mm |
| Member width | 50 | mm |
| Purlin depth | 25 | mm |
| Purlin width | 68 | mm |
| Rafter depth | 120 | mm |
| Header beam depth | 150 | mm |
| Ridge beam depth | 150 | mm |
| Column section | 65 | mm |
| Intermediate rafter pairs | 2 | |
| Columns per side | 2 | |
| Frame finish | anodisedNatural | |
| Gutters | true | |
| Gutter width | 185 | mm |
| Overall length | (sheetCount * sheetCover) | mm |
| Overall width | gutter ? gableWidth + 2 * (gutterWidth - eaveOverhang) : (gableWidth + 2 * (ribHeight * Math.sin(pitch * Math.PI / 180))) | mm |
| Overall height | ridgeUnderside + ribHeight * Math.cos(pitch * Math.PI / 180) | mm |
| Roof pitch | 22 | ° |
| Roofing rib height | 16 | mm |
| Roofing cover width | 762 | mm |
| Roofing overhang past the header | 50 | mm |
| Rafter top at the ridge | columnHeight + headerDepth + (gableWidth / 2 - eaveOverhang - beamWidth) * Math.tan(pitch * Math.PI / 180) | mm |
| Roofing underside at the ridge | ridgeRafterTop + purlinDepth / Math.cos(pitch * Math.PI / 180) | mm |
| Purlin count | Math.ceil((((gableWidth / 2 - eaveOverhang - beamWidth) / Math.cos(pitch * Math.PI / 180)) - purlinWidth) / purlinSpacing) + 1 | |
| Roof finish | steelZincAluminium |