In this guide
Measure along the roof
A sloping roof length is different from its horizontal projection. Label each slope separately and identify the intended ridge and eave termination points. State whether your dimensions already include an overhang so the same allowance is not added twice.
Record width and geometry
Measure the width along the eaves and provide pitch or rise and run. Mark valleys, rooflights, chimneys and wall connections. For a double-pitch roof, send both slope lengths rather than only the building's total span.
Turn measurements into a cutting schedule
Send a dimensioned sketch and frame photographs. Final panel lengths must allow for the agreed ridge, drainage and end-joint details. Have the cutting schedule checked before production; preliminary building dimensions are not automatically manufacturing dimensions.
Roof measurement checklist
| Field | What to provide |
|---|---|
| L / L1 / L2 | Actual slope length for each roof plane, with termination points identified |
| W | Width along the eaves, including any agreed side allowances |
| Purlin spacing | Centre-to-centre support spacing and support material |
| Pitch / rise | Slope angle or the rise and horizontal run |
| Overhang | Distance beyond the outer support; say whether it is already included in L |
| Junctions | Walls, ridge, valleys, rooflights and drainage outlets |
Single- and double-slope enquiries
For a single slope, identify the high end and the eave. For a double slope, label both roof planes and the ridge separately. Attach the sketch to the enquiry and use the confirmed production layout, rather than an unreviewed sketch, as the final cutting instruction.
Confirm the right panel and specification with GMiSU.
Send your drawings, dimensions, quantity, color, destination and target schedule for project-based recommendations.