Accurately calculate your factory shed or PEB warehouse bill of materials: total steel tonnage, sheet count, purlin spacing, and EPDM fastener requirements. Powered by certified primary mill tolerances.
Quickly estimate total steel tonnage, colour coated sheet count, purlin spacing, and fastener requirements for your roof, warehouse, or factory shed in Central India. Sourced direct from primary mills.
Understanding effective coverage width, profile girth expansion factors, and fastener distribution is crucial for avoiding site shortages and structural water leaks.
When ordering trapezoidal profile sheets, calculating shed area based on overall coil width (1072mm) leads to an immediate 5% to 7% material deficit on site.
Rule of thumb: To calculate total sheets per slope, divide your shed length in feet by 3.34 and round up to the nearest whole integer.
Purlin spacing determines structural stiffness, preventing oil-canning and sheet flutter during monsoon storms:
| TCT Gauge | Max Roof Span | Max Wall Cladding Span | Application Suitability |
|---|---|---|---|
| 0.35 mm | 1.10 m (3.6 ft) | 1.30 m (4.2 ft) | Light sheds, temporary covers |
| 0.40 mm | 1.25 m (4.1 ft) | 1.50 m (4.9 ft) | Agro sheds, poultry farms |
| 0.45 mm | 1.40 m (4.6 ft) | 1.65 m (5.4 ft) | Standard factory & warehouse |
| 0.50 mm | 1.55 m (5.1 ft) | 1.85 m (6.0 ft) | PEB Industry Standard (JSW/Jindal) |
| 0.60 mm – 0.80 mm | 1.80 m – 2.20 m | 2.20 m – 2.60 m | Heavy industrial & coastal plants |
Steel weight per square meter is calculated using the physical density of structural carbon steel (7.85 kg/m² per 1mm thickness), adjusted for roll-formed crest profile extension:
The 1.18 multiplier accounts for the 18% additional steel folded into 28mm high crest ribs and side-lap joints compared to a flat sheet.
Fastened through rib peaks into steel purlins. Vulcanized EPDM sealing washers ensure thermal expansion without water leakage.
Installed along longitudinal side-laps between purlins at 450mm intervals to prevent sheet separation under wind suction.
Submit your architectural roof drawings or shed dimensions. Our technical team in Nagpur will calculate purlin layouts, flashing details, and deliver a certified project estimate.
Divide the shed width by the effective cover width of the sheet (1020 mm or 3.34 ft). For example, a 100 ft wide shed requires 100 ÷ 3.34 = 30 sheets per slope. Shourya Roof manufactures computerized custom lengths up to 42 ft to eliminate slope end-laps.
Standard profile sheets are manufactured from 1220mm wide coils. Roll-forming folds the steel into 28mm deep trapezoidal ribs, producing an overall sheet width of 1070–1072mm. When installed, one complete crest is overlapped onto the adjacent sheet to ensure leak-proof weather protection, leaving an effective cover width of 1020mm.
For 0.50mm high-tensile 550 MPa (G550) PPGL roofing sheets, recommended purlin spacing is 1.4 meters to 1.6 meters (4.5 ft to 5.2 ft). For heavy monsoon areas or coastal corridors, purlin spacing may be kept at 1.2 meters to ensure zero sagging under wind uplift loads (IS 875 Part 3).
A general engineering standard is 4.5 to 5 fasteners per square meter of roof area. Fasteners are driven through sheet crests using 55mm self-drilling screws with EPDM washers into purlins, while 25mm stitch screws are installed every 400mm–500mm along side laps.
Structural mild steel and galvalume substrates have a standard density of 7.85 g/cm³ (7850 kg/m³). Because trapezoidal roll-forming introduces crests and valleys, the girth factor adds approximately 18% steel surface area relative to a flat plan area.