TOOLS / CONSTRUCTION

Roofing sheet quantity calculator

How many roofing sheets or PUF panels does a roof actually need, once corrugation laps are taken off the sheet size? Pick the profile by its picture, enter the roof, and get sheets per row, rows and total sheets.

Tap the picture that looks like your sheet — the name underneath is only a label. Laps are subtracted before counting, so you do not order on full sheet size.

End-lap guide: 150 mm above 15° slope, 200 mm at 10–15°, 250 mm below 10°. In severe wind/rain, use 2 corrugations side lap for wave sheets.

Sheet length suggestion

Your slope (5.00 m) is longer than your sheet (3.00 m), so you need 2 rows, with 1 end lap losing 150 mm to lapping in length.

Order sheets cut to the full slope length — 5.00 m — and you use 1 row instead: 15 sheets per row × 1 row = 16 sheets incl. waste, instead of 32. Ask your supplier if they cut to length — most trapezoidal and PUF suppliers do, up to about 12 m.

Roof area50.0 m²

Effective cover width 698 mm · effective length 2.85 m · 15 per row × 2 rows × 1 face(s) = 30 sheets before waste.

Sheets required (incl. waste)32 sheets

Total sheet area to order ≈ 77.8 m².

Estimate only. Confirm profile, cover width, lap, pitch, purlin spacing and wind exposure against the manufacturer data and the actual sheet you buy — cover widths vary by maker.

How the count works

Effective cover width = overall sheet width − side lap. Effective sheet length = sheet length − end lap. Sheets per row = roof width ÷ effective cover width, rounded up. Rows = slope length ÷ effective length, rounded up. Total = sheets per row × rows × roof faces, then waste % added and rounded up.

Worked example

Roof 10 m wide × 5 m slope, 1 face, wave sheet 810 mm, 1.5 corrugations side lap (113 mm), sheet 3 m, end lap 150 mm, waste 5%: effective width 697 mm, effective length 2.85 m, 15 sheets per row × 2 rows = 30 sheets, 30 × 1.05 = 31.5 → 32 sheets required.

Profiles and laps

Wave sheets follow IS 277 corrugation (75 mm pitch, 17.5 mm depth, Grade A). Overall widths after corrugation: 810 mm (10 corrugations) and 910 mm (11 corrugations). Modern 18/76 profile: 1076 mm overall, 1000 mm cover with a one-wave lap. PUF sandwich panels: 1000 mm cover width (1060 mm supply), 30–100 mm thick, tongue & groove joint — no extra side-lap deduction, and panels are usually ordered to the full slope length. End-lap guide for lapped sheets: 150 mm above 15°, 200 mm at 10–15°, 250 mm below 10°.