Roof Sheet Calculator
Work out how many Colorbond or Zincalume roof sheets you need and how long to order them, from the building size, roof pitch and overhangs. Cover widths and minimum pitches are from Lysaght product data.
How many roof sheets do I need?
Roof sheet profiles
Cover width is what each sheet adds across the roof once lapped. Order sheets cut to length, rounded up, and allow extra for flashings, ridge capping and barge capping.
| Profile | Type | Cover width | Minimum pitch |
|---|---|---|---|
| Lysaght Custom Orb | Corrugated | 762 mm | 5° |
| Lysaght Trimdek | Trapezoidal | 762 mm | 2° |
| Lysaght Klip-Lok 700 Hi-Strength | Concealed fix | 700 mm | 1° (1° applies to 0.48 BMT; 0.42 BMT is generally 2°.) |
Related
Frequently asked questions
How do I calculate how many roof sheets I need?
Divide the length of the roof along the gutter (plus any gable overhang) by the sheet’s cover width and round up; that is the number of sheets per roof face. Multiply by the number of faces: two for a gable roof, one for a skillion. Sheet length is the rafter run plus eave overhang divided by the cosine of the pitch.
What is the cover width of Custom Orb and Trimdek?
Lysaght Custom Orb and Trimdek both have a 762 mm cover width, and Klip-Lok 700 Hi-Strength covers 700 mm. Cover width is the width each sheet adds once lapped, which is less than the full rolled width.
What is the minimum pitch for Colorbond roof sheets?
It depends on the profile: Lysaght lists 5° for Custom Orb, 2° for Trimdek and 1° for Klip-Lok 700 Hi-Strength in 0.48 BMT. Use a lower-pitch profile for skillion roofs and patios below 5°.