Galvanized roofing sheets run 0.25–0.5 mm base thickness in corrugated, trapezoidal (IBR) and tile profiles — 0.3 mm carries purlin spacing up to about 0.9 m, 0.47 mm up to 1.4 m. Coating Z275 is the outdoor standard; a 40GP container holds roughly 1,500–1,800 sheets of 0.4 mm × 1219 mm cut at 3 m.
Roofing sheets are where GI coil becomes a building. Three decisions decide everything: base thickness (what the purlin spacing demands), profile (corrugated vs trapezoidal vs tile), and coating (how many years before first rust). Get those right and the container math follows.
Thickness vs Purlin Spacing
| Base Thickness | Max Purlin Spacing | Typical Building | Sheets per 40GP (3 m) |
|---|---|---|---|
| 0.25–0.30 mm | 0.6–0.9 m | Sheds, carports, storage | ≈ 2,300–2,600 |
| 0.35–0.40 mm | 0.9–1.2 m | Warehouses, workshops | ≈ 1,700–2,000 |
| 0.47–0.50 mm | 1.2–1.4 m | Industrial, high-wind zones | ≈ 1,400–1,500 |
Watch the thickness basis: nominal 0.4 mm vs "0.4 mm minus tolerance" (effectively 0.35) changes the span table — always confirm which basis the quotation uses.
Profiles: Which Shape for Which Building
- Corrugated (round wave): the classic — flexible, cheap, easy overlap; cover widths 760–1000 mm. Farm buildings, simple sheds.
- Trapezoidal / IBR: higher ribs, stronger spans, modern look; cover widths 860–1050 mm. Warehouses and commercial roofs.
- Tile profile: shaped like roof tiles for residential and premium builds — usually ordered in PPGI color: color guide here.
Coating: Z275 Minimum Outdoors
Bare galvanized roofing starts at Z275 for outdoor service — Z120-class sheet will rust through within a few monsoon seasons. For longer life or coastal sites: Z350+, GL aluzinc (GI vs GL guide), or step up to pre-painted PPGI. Full coating logic: Z275 guide.
Container Math, Worked
- Meters per ton at 0.4 mm × 1219 mm = 261 m (full tables).
- Cut at 3.0 m per sheet → 87 sheets per ton.
- 40GP payload 26 t → ≈ 2,260 sheets ≈ 2,070 m² of roof coverage with overlap.
- Order with ridge caps, flashing and fasteners mixed in — no second shipment for trim.
Sheets ship banded on wood pallets, interleaved, capped against transit damage; coil supply for your own roll-former also available: GI coil product page →
Roof dimensions in, container plan out
Profile, thickness, sheet length and roof area to [email protected] or WhatsApp +86 191 5745 8011 — sheets-per-container plan and FOB/CIF price in one working day. MOQ 5 t.
Request Roofing Sheet Quote