L-Return Valley Truss Roof

A gabled roof with a return wing flush with one end of the main roof, framed with plated timber trusses: Fink trusses in the main run and in the wing with a two-ply girder at the junction, and valley trusses stepping down inside the wing footprint. Main length and span, wing span and length, 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
Wing Span	5000	mm
Wing Length	6000	mm
Pitch	30	°
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 + wingLength + overhang + plateThickness	mm
Depth	length + overhang + chordThickness / 2 + plateThickness	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
Saddle Truss Minimum Span	Math.max(2 * 600 / slope, 2 * (heel + chordDepth + webDepth) / slope)	mm
Wing Centre	length - wingSpan / 2	mm
Valley Truss Spaces	Math.ceil(wingSpan / 2 / maximumSpacing)
Valley Truss Spacing	wingSpan / 2 / valleyBays	mm
First Valley Truss	Math.ceil(Math.max(saddleMinSpan, maximumSpacing) / (2 * valleyStep))
Valley Trusses	Math.max(valleyBays - firstValley, 0)