What is Trapezoidal sheet 38/151?
The 38/151 — T38, T40 in some European catalogues, close to the RN38 and the British 32/1000 family — is the roof profile of the steel-building trade: six trapezoidal ribs 38 mm deep at 151 mm centres on a 906 mm cover, rolled from a 1 250 mm coil, with 60 mm crests, 70 mm pans and sloping webs that stiffen the sheet and shed water. The extra depth over the T27 buys two things: bending stiffness, so the sheet spans 2–3 m between purlins under snow and wind (the purlin spacing of most portal frames), and drainage capacity, so a 30–40 m roof slope at 7–10 % pitch runs dry without ponding. It is used as the outer sheet of single-skin roofs and of built-up roofs (over a liner and insulation), as wall cladding where a stronger rib pattern is wanted, and as the skin of site-assembled canopies and hangars. Material is DX51D or S280GD galvanized (Z100 in dry climates, Z140–Z275 exposed, coastal and Gulf) or PPGI in the stock colours — 9002 grey white dominates industrial roofs, 3009 rural ones, 7016 modern ones — in 0.40 mm for light roofs and walls, 0.50 mm as the standard, 0.60–0.70 mm for snow regions and long spans. Sheets are rolled to any length up to 14 m so that most roof slopes are covered in one piece without end laps; the profile is symmetric and can be laid from either side. We roll T38 on our Dilovası line, fold the ridge, eaves, verge and wall flashings from the same coil, and supply foam closures, self-drilling screws with EPDM washers and sealant so that the roof arrives complete.
Grades, standards and tolerances
| Grade / standard | Yield (MPa) | Note |
|---|---|---|
| DX51D+Z100 (EN 10346) | ≈ 140 (not guaranteed) | inland roofs, dry climates |
| DX51D+Z140 / Z275 | ≈ 140 | exposed, coastal, Gulf |
| S280GD+Z275 | 280 | spans to 3 m, snow loads |
| S320GD+Z275 | 320 | long spans, to order |
| PPGI (Z100 + PE / SMP / PVDF) | ≈ 140 | coloured roofs, EN 10169 |
Load-span data are calculated for S280GD; DX51D sheet is used at the conservative end of the table.
Profile dimensions and span table
| Item | 0.40 mm | 0.50 mm | 0.60 mm | 0.70 mm |
|---|---|---|---|---|
| Rib height / pitch | 38 / 151 mm | 38 / 151 mm | 38 / 151 mm | 38 / 151 mm |
| Ribs · cover width · overall | 6 · 906 · 970 mm | same | same | same |
| Weight per m² covered (galv.) | 4.4 kg | 5.5 kg | 6.6 kg | 7.7 kg |
| Purlin spacing, 0.75 kN/m² | 1.7 m | 2.1 m | 2.5 m | 2.9 m |
| Purlin spacing, 1.0 kN/m² | 1.5 m | 1.9 m | 2.2 m | 2.6 m |
| Purlin spacing, 1.5 kN/m² | 1.2 m | 1.6 m | 1.9 m | 2.2 m |
| Purlin spacing, 2.0 kN/m² (snow) | 1.1 m | 1.4 m | 1.7 m | 1.9 m |
| Wall girt spacing, 0.6 kN/m² wind | 2.0 m | 2.4 m | 2.8 m | 3.1 m |
| Min. roof slope | 7 % (4°) | 7 % | 7 % | 7 % |
| Max. length | 14 m | 14 m | 14 m | 14 m |
Loads are total (dead + snow / imposed) on the roof; wind uplift and fixing pull-out may govern on exposed sites. CE load tables for the project case are supplied with the offer.
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 the Gulf and coastal Africa specify Z275 galvanized or PVDF PPGI; 0.50 mm is the standard roof gauge, 0.60–0.70 in snow regions.
Roof accessories rolled and folded to match
| Item | Size | Material | Note |
|---|---|---|---|
| Ridge cap | 2 × 200–300 mm, 3 m | same coil | plain or profiled |
| Eaves and verge flashings | to drawing, 3–6 m | same coil | |
| Wall / parapet flashings | to drawing | same coil | |
| Foam closures | T38 profile | PE foam | eaves and ridge |
| Self-drilling screws | 5.5 × 55–65 mm | zinc-flake, EPDM washer | painted heads for PPGI |
| Stitching screws | 4.8 × 20 mm | stainless / zinc | side laps |
| Butyl sealant tape | 3 × 10 mm | — | end laps, low slopes |
| Gutters and downpipes | to drawing | same coil | on request |
Ordering the accessories with the sheets keeps the whole roof in one colour batch.
Lengths and stock
T38 galvanized 0.50 mm and PPGI 9002 / 3009 / 7016 in 0.45–0.50 mm are rolled continuously and available in 3–7 working days at any length to 14 m; 0.40, 0.60 and 0.70 mm and other colours in about two weeks. Every order can ship with ridge, flashings, closures and screws.
Fixing, lapping and installation
Fix through the rib crests at every purlin with 5.5 × 55–65 mm self-drilling screws and 19 mm EPDM washers — every rib at eaves, ridge and end laps, every second rib elsewhere; stitch side laps at 500 mm with 4.8 mm screws. Side lap one rib laid against the prevailing wind, end lap 200 mm with butyl tape (150 mm above 15 % slope); avoid end laps by ordering full-slope lengths. Cut with a nibbler, shears or cold saw; walk on the pans at purlin lines only. Foam closures at eaves and ridge, and a ventilated ridge on unlined roofs to limit condensation.
Where it is used
- Roofs of warehouses, factories, workshops and hangars
- Outer sheet of built-up insulated roofs
- Agricultural buildings, stables and stores
- Canopies, car ports and loading bays
- Wall cladding with a strong rib pattern
- Re-roofing over existing purlins
T38 vs T27 vs 45/333
The T27 is the wall and liner profile and a roof only at close purlins; the 45/333 is deeper still for 3–4 m spans and deck use. T38 is the general-purpose roof between them — for most portal frames the right answer. Galvanized and coloured versions are compared on the galvanized and PPGI trapezoidal pages.
Price
T38 is priced per m² covered by material and gauge on the roofing list, following the galvanized coil price; the bands below are the month\'s indicative FOB Istanbul ranges for galvanized and PPGI 0.50 mm. Accessories are priced per metre and 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
T38 ships in packs of 30–50 sheets with paper between coloured faces, strapped on timber bearers with edge boards and PE-wrapped, labelled with profile, material, gauge, length and count; 2 400–2 800 m² of 6 m sheets per 40' HC (≈ 13 t), 12–14 m sheets on flat-rack or breakbulk from Derince. Flashings, closures and screws are packed separately in the same load. HS 7210.41 / 7210.70 or 7308.90.
| 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; other colours 2 weeks |
| Packing | Packs of 30–50 sheets on timber, strapped, PE-wrapped, paper interleaved for PPGI |
| Container / truck | 40' HC ≈ 2 400–2 800 m² of 6 m sheets; 12–14 m on flat-rack |
| 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
Each order carries the coil mill\'s EN 10204 3.1 (grade, zinc mass, paint system) and our CE declaration of performance under EN 14782 with the load-span table of the profile; a colour-match sample and the paint warranty document are supplied on request.
How to order
Specify galvanized (zinc class) or PPGI (RAL, system), thickness, sheet lengths and quantities per length (or the roof plan for a cutting schedule), ridge / flashing / closure / screw needs, and destination; state the snow or wind load if you want the gauge confirmed.
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 trapezoidal sheet 38/151?
The standard industrial roof profile: 38 mm-deep ribs at 151 mm pitch, six ribs on a 906 mm cover, rolled from galvanized or pre-painted coil 0.40–0.70 mm; spans 2–3 m between purlins.
What purlin spacing does T38 need?
About 2.1 m for 0.50 mm at 0.75 kN/m², 1.6 m at 1.5 kN/m²; 0.60–0.70 mm reaches 2.5–2.9 m — see the span table.
What is the minimum roof slope for T38?
7 % (4°) with sealed 200 mm end laps; 10 % is comfortable, and full-length sheets without end laps are best.
Which thickness should I choose?
0.50 mm is the standard roof gauge; 0.40 mm for light roofs and walls; 0.60–0.70 mm for snow regions, long spans or foot traffic.
How many m² of T38 fit in a container?
About 2 400–2 800 m² of 6 m sheets (≈ 13 t) in a 40' HC; longer sheets go on flat-racks.
What is the price of T38 roofing sheet?
Per m² FOB Istanbul by material and gauge — see the bands above.