Jack Truss
A plated timber jack truss, the mono-pitch hip-end truss that is carried by the truncated girder at its high end and bears on the wall plate at its low end: a ceiling tie, a rafter with its tail over the wall, a post at the high end and one raking web from mid span to the foot of the post, drawn as members without connector plates. Span from the wall plate to the girder, pitch and overhang, Member thickness and chord and web depths
Details
Category: Roof Framing › Hip Truss Roofs › Hip Set Trusses
By Huu Khanh Nguyen · Updated November 4, 2026
Parameters
| Name | Default | Unit |
|---|---|---|
| Span | 3000 | mm |
| Pitch | 25 | ° |
| Overhang | 450 | mm |
| Member Thickness | 35 | mm |
| Chord Depth | 97 | mm |
| Web Depth | 70 | mm |
| Slope | Math.tan((pitch * Math.PI / 180)) | |
| Heel Height | chordDepth * Math.sqrt(1 + slope * slope) | mm |
| Width | span + overhang | mm |
| Depth | chordThickness | mm |
| Height | (span) * slope + heelHeight + overhang * slope | mm |