Hip Roof GeometryEnter the wall plate size, pitch and overhang of an equal-pitch hip roof. Get the true hip rafter length, the backing angle, every jack rafter and the roof area, drawn on a live plan.

SheetT-55
MethodSolid geometry, 45° hips
Unitsm, mm, degrees
By@smart_tools_every_week
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Every face has the same pitch, so the hips run at 45° in plan and the ridge is the length minus the width. A square plan gives a pyramid roof with no ridge. Jack rafters run from the eaves up to a hip; the list is for one face next to one hip, and every hip has the same set on both sides.

Hip rafter–
Common rafter–
Backing angle–
Roof area–

Roof plan

Section across

Hip, true length

Jack rafters, one face of one hip

JackFrom cornerCentre-line lengthCut lengthPer roof

Cutting summary

MemberNumberLength eachTotal