What is Corrugated roofing sheet 18/76?
The 18/76 corrugated sheet is the sinusoidal profile that has roofed sheds since the 1830s, brought up to date in material: instead of the old 26-gauge galvanized iron it is rolled from continuously hot-dip galvanized DX51D coil (Z100–Z275) or pre-painted PPGI, 0.40–0.70 mm thick, on a roll-former that forms the 18 mm-high, 76 mm-pitch wave without stretching the coating. A sheet of 1 076 mm overall covers 1 000 mm net with a one-wave side lap and is made to any length from 1 to 12 m; the profile is symmetric, so there is no up/down or left/right, and its shallow waves let it be curved on the line to radii from 1.5 m for barrel-vault roofs, canopies and silos. Its structural performance is modest — the 18 mm depth spans about 1.0–1.5 m between purlins under a normal roof load — so it belongs on closely purlined roofs, walls, fences and light structures; where purlins are 2 m or more apart, the 27/150 or 38/151 trapezoidal profiles take over. What it keeps is the look and the forgiveness: a wavy roof reads as traditional, the side laps seal well with a single fixing through the crest, and damaged sheets are replaced one at a time. We roll galvanized and PPGI 18/76 from the same coils as our trapezoidal sheets, cut to length, with ridge caps, corner and eaves flashings, and crest-fix screws with EPDM washers or hook bolts for purlin fixing.
Grades, standards and tolerances
| Grade / standard | Yield (MPa) | Note |
|---|---|---|
| DX51D+Z100 (EN 10346) | ≈ 140 (not guaranteed) | galvanized, general roofing |
| DX51D+Z140 / Z275 | ≈ 140 | exposed and coastal |
| S280GD+Z275 | 280 | longer spans, snow / wind loads |
| PPGI (DX51D+Z100 + PE 25 µm) | ≈ 140 | coloured sheet, EN 10169 |
Profile tolerances per EN 14782: length ±10 mm, cover width ±5 mm, wave height ±1 mm.
Profile dimensions and span
| Item | Value |
|---|---|
| Wave height | 18 mm |
| Wave pitch | 76 mm |
| Waves per sheet | 14 |
| Overall width | 1 076 mm |
| Cover width | 1 000 mm (one-wave side lap) |
| Length | 1–12 m, to order |
| Min. curving radius | 1.5 m (0.50 mm), 2.5 m (0.70 mm) |
| Weight 0.40 / 0.50 / 0.70 mm | 3.6 / 4.5 / 6.3 kg/m² covered |
| Purlin spacing, roof 0.75 kN/m² | 1.0 m (0.40) · 1.2 m (0.50) · 1.5 m (0.70) |
| Purlin spacing, wall | 1.5–2.0 m |
| Min. roof slope | 15 % (8.5°) with 200 mm end lap; 10 % with sealed laps |
Spans are for continuous two-span sheets at L/150 deflection; check wind uplift and fixing pull-out for exposed roofs.
Material, thickness and weight
| Material | Thickness (TCT) | kg/m² covered | Colours | Life (C3 / coastal) | Note |
|---|---|---|---|---|---|
| Galvanized DX51D+Z100 | 0.40–0.50 | 3.6–4.5 | spangle silver | 10–15 / 5–8 yr | cheapest; warehouses, sheds |
| Galvanized Z140–Z275 | 0.50–0.70 | 4.5–6.3 | silver | 15–25 / 8–12 yr | exposed roofs, agriculture |
| PPGI PE 25 µm on Z100 | 0.40–0.60 | 3.7–5.5 | RAL 9002, 9010, 3009, 7016, 6005 … | 10–15 / 5–8 yr | the standard coloured roof |
| PPGI SMP / HDP | 0.50–0.60 | 4.6–5.5 | as above | 15–25 / 10–15 yr | warranty projects |
| PPGI PVDF | 0.50–0.70 | 4.6–6.4 | as above | 25–30 / 15–20 yr | façades, Gulf coast |
| Aluzinc AZ150 | 0.45–0.60 | 4.0–5.4 | matt silver | 25–30 / 12–15 yr | to order, 10 t |
For fences and sheds 0.40 mm galvanized is the market standard; for roofs 0.50 mm; coastal sites need Z275 or PVDF PPGI.
Lengths and stock
Galvanized 0.40 and 0.50 mm and PPGI RAL 9002 / 3009 / 7016 in 0.40–0.50 mm are rolled continuously and normally available in 2, 3 and 6 m within a week; other lengths (to 12 m), gauges to 0.70 mm, curved sheets and other colours are rolled to order in about two weeks. Ridge caps, eaves and verge flashings, hook bolts and crest screws ship with the sheets.
Fixing, lapping and curving
Fix through the wave crests (never the troughs) with 5.5 × 55–65 mm self-drilling screws and EPDM washers into steel purlins, or with hook bolts on angle purlins — every second wave at the eaves and ridge, every third elsewhere, and stitch the side laps at 500 mm. End laps 200 mm (150 mm above 20 % slope), side lap one wave, laid against the prevailing wind. Cut with shears or a nibbler, not an abrasive disc. Curved sheets are formed on our crimp-curving machine to the drawing radius; on site the sheet can be sprung to radii above 8 m.
Where it is used
- Sheds, barns, workshops and rural roofs
- Fences, hoardings and site boundaries
- Wall cladding of light industrial buildings
- Curved roofs, canopies, silos and market stalls
- Re-roofing of old corrugated-iron buildings
- Temporary and relief housing
Corrugated vs trapezoidal sheet
The corrugated sheet is lighter, curves and looks traditional but spans only 1–1.5 m; the 27/150 trapezoidal spans 1.5–2 m and the 38/151 2–3 m on the same gauge, which is why industrial roofs use them. The roofing sheet overview compares all profiles; for a tile look, the tile-profile sheet.
Price
Corrugated sheet is priced per m² covered by material and gauge — galvanized 0.40 mm is the entry price of the roofing list, PPGI 0.50 mm the standard coloured roof — and follows the galvanized coil price; the bands below are the month\'s indicative FOB Istanbul ranges. Ridges and flashings per metre, screws per hundred.
Bands from our weekly export list (September 2026), FOB Istanbul, full-container quantities, excluding freight and certificates. Firm price per project on RFQ within one working day.
Export and packing
Corrugated sheets are stacked 30–60 per pack with paper between coloured sheets, strapped on timber bearers with edge boards and PE-wrapped; packs are labelled with profile, material, gauge, length and count. A 40' HC takes 2 500–3 000 m² of 6 m sheets (about 12 t), a 20' 1 200–1 500 m² of 3 m; 12 m sheets go on flat-rack. Curved sheets are nested and crated. HS 7210.41 / 7210.70 (coil origin) or 7308.90 as roofing.
| Term | Detail |
|---|---|
| MOQ | 300 m² per colour and gauge |
| Incoterms | FOB Istanbul · CIF / CFR Gulf, Africa · DAP EU, Balkans, Iraq, Caucasus · DAP Aktau |
| Lead time | Stock colours and galvanized: 3–7 working days; 12 m and special colours 2 weeks |
| Packing | Sheets stacked 30–60 per pack on timber bearers, strapped, PE-wrapped, edge boards; nested curved sheets crated |
| Container / truck | 20' ≈ 1 200–1 500 m² (≈ 6–7 t); 40' HC ≈ 2 500–3 000 m² of 6 m sheets |
| Documents | Invoice, packing list, EN 10204 3.1 (coil), CE DoP (EN 14782), certificate of origin; SASO / SONCAP on request |
| Payment | 30% advance, balance against B/L copy; L/C at sight above 100 t |
Certificates
Corrugated 18/76 ships with the coil mill\'s EN 10204 3.1 (grade, zinc mass, paint system) and our CE declaration of performance under EN 14782 (profile, thickness, load-span data); a colour-match sample and the coating warranty (PE / SMP / PVDF) are supplied on request.
How to order
Specify galvanized (zinc class) or PPGI (RAL colour, system), thickness, sheet lengths and quantity per length (or the roof m² and slope for us to cut a schedule), curved sheets with radius, accessories and destination.
Standards
- EN 14782 — self-supporting metal sheet for roofing and cladding
- EN 10346 — DX51D / S280GD + Z100–Z275 substrate
- EN 10169 — coil-coated (PPGI) substrate
- EN 1993-1-3 — cold-formed design; EN 10204 3.1
Grades
Grade data sheets (chemistry, mechanicals, equivalents) are on our reference site: DX51D · S280GD · S320GD
Frequently asked questions
What is 18/76 corrugated sheet?
The classic sinusoidal roofing sheet with 18 mm-high waves on a 76 mm pitch, rolled from galvanized or pre-painted coil 0.40–0.70 mm, covering 1 000 mm per sheet — used on sheds, barns, fences, walls and curved roofs.
What purlin spacing does corrugated sheet need?
About 1.0 m for 0.40 mm, 1.2 m for 0.50 mm and 1.5 m for 0.70 mm under a normal roof load; 1.5–2 m on walls.
Can corrugated sheet be curved?
Yes — crimp-curved on our line to radii from 1.5 m (0.50 mm) for barrel roofs, canopies and silos; on site it springs to radii above 8 m.
Which thickness for a roof?
0.50 mm for roofs and exposed walls, 0.40 mm for fences, sheds and light cladding, 0.60–0.70 mm for snow or wind-loaded roofs.
What is the price of corrugated roofing sheet?
Per m² FOB Istanbul — see the bands above; galvanized 0.40 mm is the cheapest metal roofing there is.