Hip Truss Roof

A hipped roof framed with plated timber trusses over a rectangular plan: Fink trusses in the main run, and at each end a truncated girder, truncated standard trusses, two hip trusses, jack trusses between the hips and creepers in the corners. Plan length and span over the wall plates, Pitch, largest truss spacing and overhang, Member and plate thickness, depths, Wall height and thickness

Details

Category: Roof Framing › Timber Roof Framing › Hip and Valley Roofs

By Huu Khanh Nguyen · Updated November 5, 2026

Parameters

Name	Default	Unit
Length	9000	mm
Span	7000	mm
Pitch	25	°
Maximum Truss Spacing	600	mm
Overhang	450	mm
Member Thickness	35	mm
Chord Depth	97	mm
Web Depth	70	mm
Plate Thickness	1	mm
Wall Thickness	90	mm
Wall Height	2400	mm
Width	span + 2 * overhang	mm
Depth	length + 2 * overhang	mm
Height	span / 2 * slope + heel + wallHeight	mm
Slope	Math.tan(pitch * Math.PI / 180)
Heel Height	chordDepth / Math.cos(pitch * Math.PI / 180)	mm
Girder Set Back Fraction	0.34
Girder Set Back	girderFraction * span	mm
Hip Plan Angle	45	°
Truncated Standards per End	Math.max(Math.ceil((0.5 - girderFraction) * span / maximumSpacing) - 1, 1)
Truncated Standard Gap	(0.5 - girderFraction) * span / (truncatedCount + 1)	mm
Row Count	Math.ceil(span / maximumSpacing)
Row Spacing	span / rowCount	mm
First Creeper Row	Math.ceil((2 * chordDepth / slope + chordThickness / Math.SQRT2) / rowSpacing)
First Jack Row	Math.ceil(girderFraction * rowCount - 1e-9)
Creepers per Corner Side	Math.max(firstJackRow - firstCreeperRow - (girderSetBack - (firstJackRow - 1) * rowSpacing < chordThickness + 2 * plateThickness ? 1 : 0), 0)
Jacks per End	Math.max(rowCount - 2 * firstJackRow + 1, 0)