Corrugated Steel Sheet: Base Materials, Wave Profiles and Coating Selection
Jan 31, 2024
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Corrugated steel sheet, also called profiled or pressed sheet, is made by cold roll-forming colour-coated steel sheet, galvanized sheet or another metal plate into a repeating wave shape. It is the standard material for industrial and civil building roofs and walls, and the same product family serves partitions, ceilings and equipment enclosures.
Base Materials and Specifications
The profile is only as good as the coil it is formed from. Substrates are hot-dip galvanized or cold-rolled material, and the zinc mass together with the paint system decides the service life of the finished panel.
| Parameter | Range or option |
|---|---|
| Base coil | SGCC, SPCC, DC51D, SGHC, ASTM A653 galvanized or cold-rolled substrate |
| Thickness | 0.12 - 2.00 mm |
| Width | 600 - 1250 mm before forming |
| Zinc coating | 30 - 275 g/m² per side |
| Paint system | Polyester, silicone-modified polyester or PVDF topcoat |
| Colour | Customisable pre-painted finishes |
| Standards | JIS G3302, ASTM A653, EN 10346 for the base sheet; GB/T 12755 for profiled sheet |
Thin gauges near 0.12-0.30 mm are used for decorative linings and light roofing, while 0.50-2.00 mm material carries structural roof and wall loads. Zinc coating below 100 g/m² suits dry inland service; 180-275 g/m² is specified for coastal or heavily polluted atmospheres.
Corrugated Sheet and Colour-Coated Sheet
The two terms describe the same material family at different processing stages. Corrugated or profiled sheet is the formed product that has been cold-bent into waves by roll forming, whereas colour-coated sheet is the flat pre-painted coil or cut sheet. Colour-coated products are supplied as single sheets, as composite sandwich panels and as floor deck sheets.
Because forming takes place after coating, the paint system must tolerate bending without cracking. Coating adhesion, pencil hardness and flexibility are therefore inspected on the finished panel, not only on the flat coil.
Classification by Wave Height
| Type | Wave height | Typical use |
|---|---|---|
| High wave | 70 mm and above | Standing seam or concealed-fix roof panels with high watertightness requirements |
| Medium wave | 50 - 70 mm | General roofs and wall panels |
| Low wave | Below 30 mm | Wall cladding and decorative panels |
Wave height, pitch and the number of ribs determine the section modulus of the panel. For a given span and wind load, a deeper profile allows thinner steel, so the profile is always selected together with the thickness rather than independently.
Properties and Expected Service Life
Light weight: roughly 10-14 kg/m², about one thirtieth of a brick wall of the same area.
Load-bearing capability: usable as a self-supporting enclosure for roofs, walls and ceilings; simple buildings may need no beams or columns.
Colour stability: no additional surface finishing is required, and a sound coating system has a repaint or maintenance cycle of about 10-15 years.
Fast construction: roll-formed panels with quick-fix systems can shorten the construction cycle by more than 40%.
Thermal movement: the panels expand and contract with temperature, so fixing details must allow movement at laps and ridge lines.
Uses, Fixing and Detailing
Corrugated sheet is used mainly in construction: roofs and walls of industrial and civil buildings, warehouses, special-purpose buildings and large-span steel structures, together with interior and exterior wall cladding, commercial facilities and equipment housings.
Wave height and sheet thickness are selected from the span, the wind load and the watertightness requirement. Fasteners should be self-drilling screws with sealing washers, driven on the crest of the wave rather than in the pan, and end laps and side laps must be correct because they control most leakage. For low-pitch roofs a sealant is applied at the laps, and the recommended minimum pitch follows the profile depth.
Frequently Asked Questions
Q: What is the difference between corrugated sheet and colour-coated sheet?
Corrugated sheet is the roll-formed wave profile, while colour-coated sheet is the flat pre-painted material. The corrugated panel is normally produced from a colour-coated or galvanized coil.
Q: Which zinc coating should be specified?
Dry inland buildings are usually served by 60-100 g/m², general outdoor exposure by about 120-180 g/m², and coastal or heavy industrial environments by 180-275 g/m² combined with a PVDF topcoat.
Q: Which thickness is needed for a roof?
It depends on purlin spacing and wind load. Typical roof panels are 0.40-0.80 mm, while wall cladding can go down to 0.30 mm and heavy spans use 1.00 mm or more.
Q: How long does a coated panel last?
A well-formed panel with an adequate zinc layer and a sound topcoat has a maintenance cycle of roughly 10-15 years, but cut edges, scratches and drilled holes must be touched up to avoid early corrosion.
Q: Why do roofs leak at the fasteners?
Most leaks come from screws driven without sealing washers, overtightened screws that deform the washer, and missed sealant at low-pitch end laps rather than from the steel itself.
Q: Can corrugated sheet be used as a structural element?
Yes. Deep profiles act as load-bearing enclosure panels, and in simple buildings they can carry roof and wall loads without separate beams or columns when the span and support conditions allow.