Metal Roof Sheets are roll-formed from steel or alloy coils into corrugated profiles used for roof and wall cladding. The coil materials include hot-dip galvanized steel, Al-Zn coated steel, pre-painted steel, aluminum-magnesium-manganese alloy, and stainless steel. The corrugated profile increases bending stiffness along the rib direction, allowing thin sheets from 0.5 mm to 1.5 mm to carry roof loads. SENBO supplies these panels with material certificates and profile inspection records, and the production process includes regular checks on rib geometry, sheet thickness, and coating condition.
A complete metal roof system typically uses multiple layers. An airport terminal roof with a stainless steel outer sheet may include from bottom to top: galvanized primary purlins, a perforated Al-Zn coated base sheet, a vapor control layer, sound-absorbing rock wool, galvanized secondary purlins, thermal insulation rock wool, a galvanized steel sheet, a TPO waterproofing membrane, stainless steel fixing brackets, acoustic foam, the stainless steel roof panel, and a stainless steel cap. This assembly combines structural support, thermal control, air and vapor management, acoustic performance, and weather protection.
| Performance Indicator | Parameter / Specification | Basis or Remarks |
|---|---|---|
| Executive Standard | GB/T 12755-2008 | Profiled steel sheets for building |
| Design References | 24CJ113-1, 26CJ113-5 | National standard design details for metal sheet buildings |
| Base Material | Galvanized / Al-Zn coated / Pre-painted / Al-Mg-Mn / Stainless steel | Selected based on environment |
| Common Thickness | 0.5–1.5 mm | Stainless steel typically 0.5 mm |
| Yield Strength | 210–550 MPa | Depends on base material grade |
| Galvanizing Mass | 40–275 g/m² | Double-sided coating |
| Wind Pressure Resistance | ≥18 kPa for welded stainless steel system | Equivalent to Category 17 typhoon |
| Waterproofing Grade | Grade I | Structural waterproofing |
| Design Service Life | 15–50 years | Depends on base material |
The continuously welded stainless steel roof at Guangzhou Baiyun International Airport Terminal 3 underwent wind tunnel and static uplift tests. The recorded capacity was 18.2 kPa, which corresponds to a Category 17 typhoon. For comparison, conventional aluminum-magnesium-manganese standing seam roofs typically resist Category 12 conditions. The Greater Bay Area Cultural and Sports Center stadium uses an embedded continuously welded stainless steel roof system and reached 21 kPa in laboratory tests. The continuous welding approach eliminates the interlocking seam as a weak point and improves overall uplift resistance.
Standing seam systems achieve weather tightness through mechanically locked seams with sealant pre-applied in the joint. Welded stainless steel systems use full-length welding to create a continuous surface without seam openings. At the Greater Bay Area Cultural and Sports Center, the drainage design included optimized gutters and water-retaining walls. A double-layer flexible membrane was used below the metal surface to avoid fastener penetrations through the waterproofing layer.
Thermal expansion and contraction must be accommodated in long roof runs. At Guangzhou Baiyun Airport Terminal 3, welded connections work together with transverse corrugations in the panel profile to absorb thermal stress. This approach helps maintain the roof's structural integrity over time and reduces the risk of fatigue cracking at fixed points.
The Greater Bay Area Cultural and Sports Center used a modular strategy for the roof structure below the waterproofing membrane. The 78,000 m² roof was divided into 878 modules, which were assembled and welded on the ground and then hoisted into position. This method increased installation efficiency by 30% and kept material waste near 2%, particularly beneficial for complex curved roof geometries.
Suppliers should provide mill test certificates for the base metal, coating thickness reports, and panel profile dimensional checks. For projects with specific wind load requirements, wind uplift test reports for the exact system configuration should be available. On-site receiving inspections should verify material grades, panel lengths, rib profiles, and surface condition before installation begins.
Continuous welding of stainless steel panels offers the highest measured wind uplift resistance and is often specified for typhoon-prone regions. Standing seam systems can also perform well when seam and clip details are reinforced according to wind tunnel or uplift test data.
Standing seam systems use sliding clips that allow movement along the roof slope. Welded systems may incorporate transverse corrugations or expansion joints. The specific method should be confirmed by the roof system designer based on the building geometry and temperature range.
Periodic inspections should check for loose fasteners, damaged panels, blocked drainage paths, and sealant condition at penetrations. Standing seam and welded systems generally require less maintenance than exposed-fastener roofs because fasteners are not directly exposed to weather.
In some cases, a new metal roof can be placed over an existing roof if the structure can support the added load and the existing surface is compatible. A structural engineer must evaluate the existing conditions and confirm that the attachment details are suitable.
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