Choose a task
Learn the terms first if pitch, angle and multiplier are unfamiliar. Use the measurement and span guides before entering dimensions. Use the area and sectioning guides for multi-plane projects.
Every guide gives an immediate answer, a worked relationship, a calculator link, limitations and a review date.
Guides
Roof Pitch Slope Angle and MultiplierUnderstand the four common descriptions of roof steepness and how they relate.How to Measure Roof Pitch SafelyUse plans, accessible interior information or ground-based measurements without climbing onto a roof.Roof Span vs Horizontal RunDistinguish total building span from the one-side horizontal run used in roof triangles.Plan Area vs Roof Surface AreaUnderstand the difference between horizontal footprint and sloping planar roof surface.Common Rafter Geometry and LimitsFollow the right-triangle line calculation without treating it as structural or cutting advice.Gable Roof GeometryModel a supported symmetric gable as two planar slopes meeting at a centred ridge.Shed and Mono Pitch Roof GeometryModel a supported one-plane roof from horizontal run, pitch and plan area.Hips Valleys Dormers and IntersectionsUnderstand why complex roof junctions cannot be reduced to one slope multiplier.Overhang Eave and Ridge AdjustmentsKeep horizontal line adjustments explicit when calculating slope length or plan area.Metric and Imperial Roof MeasurementUse exact length conversions while keeping pitch ratios independent of unit choice.Divide an Irregular Roof into SectionsRecord an irregular project as separately measured supported planar sections.Read Check and Export Roof ResultsDistinguish calculated values, user assumptions and warnings in a RoofFigured record.