Deep trapezoidal steel roofing for wide purlin spacing, built for strength and durability.
Key Specifications:
Ideal For: Industrial warehouses, commercial buildings, agricultural structures, residential roofing, carports, and wall cladding applications where structural efficiency and long-term durability are essential.
Deep trapezoidal steel roofing for wide purlin spacing, built for strength and durability. BOMIS offers versatile and cost-effective roofing solutions.
1. Galvanized IBR: Hot-dipped zinc-coated steel providing dependable corrosion protection at the most economical price point. Recommended for general industrial roofing, agricultural structures, and applications where functional performance takes priority over aesthetic requirements. The zinc layer provides both barrier and sacrificial protection, delivering decades of service in standard atmospheric conditions.
2. Zincalume IBR: A zinc-aluminum alloy coating that offers significantly enhanced corrosion resistance compared to standard galvanized finishes. The aluminum component forms a stable oxide layer while the zinc provides galvanic protection at cut edges and scratches. Particularly suited for coastal installations and high-humidity environments where traditional galvanized coatings may require more frequent maintenance.
3. Color-Coated IBR (PPGI): Pre-painted galvanized or Zincalume substrate with a durable polyester, silicon-modified polyester (SMP), or PVDF coating system. Available in a wide range of standard colors with custom color matching available for volume orders. The factory-applied finish eliminates on-site painting, reduces installation time, and provides consistent color uniformity across the entire roof area.
| Paramɛtrɛ | Standard Range | Notes |
|---|---|---|
| Profile Type | IBR (Inverted Box Rib) | Trapezoidal rib geometry |
| Effective Coverage Width | 686 mm | Installed width after overlap |
| Etando ya bonene | 0.40 mm – 0.80 mm | 0.40 / 0.50 / 0.58 / 0.80 mm standard |
| Length Range | 1.5 m – 14.0 m | Custom lengths available on request |
| Length Tolerance | -0 / +5 mm | Standard range only |
| Minimum Roof Pitch | 5° (approx. 1:12) | Required for proper water drainage |
| Zinc Coating (Galvanized) | Z60 – Z275 | Higher coating weights for coastal/industrial environments |
| Paint System (PPGI) | PE / SMP / PVDF | 15-25 μm primer + topcoat per side |
1. High Strength-to-Weight Ratio: The trapezoidal rib profile delivers superior structural performance without excessive material weight. This enables longer spans between purlins — typically reducing the number of support members by 15-25% compared to conventional corrugated profiles — translating to lower substructure costs for the overall project.
2. Efficient Water Run-Off: The deep rib channels facilitate rapid water drainage, making IBR suitable for low-pitch applications down to 5 degrees. This characteristic is particularly valuable in regions with heavy rainfall where standing water on roof surfaces must be minimized to prevent leaks and premature coating degradation.
3. Installation Efficiency: With an effective coverage of 686 mm per sheet and lengths up to 14 meters, IBR sheeting minimizes the number of sheets and end-laps required. Fewer joints mean faster installation, reduced labor costs, and fewer potential leak points across the roof assembly.
4. Versatile Aesthetic Integration: The clean, linear rib pattern complements both modern architectural designs and traditional industrial aesthetics. Available in bare metallic finishes for utilitarian applications or factory-applied color coatings for projects where visual impact matters.
5. Proven Long-Term Durability: Manufactured from hot-dipped galvanized or Zincalume steel coil conforming to international standards (ASTM A653, EN 10346, AS 1397), BOMIS IBR sheeting is engineered for 20-30+ years of service life when properly installed and maintained in appropriate environments.
6. Fully Recyclable: Steel roofing is 100% recyclable at end-of-life without loss of material properties, supporting green building certifications and sustainability objectives for environmentally conscious projects.
BOMIS recommends the following professional installation guidelines to achieve optimal long-term performance from IBR roof sheeting:
Roof Pitch: A minimum slope of 5 degrees is recommended for effective water drainage. For very low-pitch applications (below 7 degrees), additional joint sealing measures are suggested to prevent capillary water ingress at side laps.
Fastener Selection: Galvanized or stainless steel self-drilling screws with EPDM sealing washers are the standard recommendation. Fasteners should be installed through the crown (peak) of the rib — never through the pan (valley) — to maintain the roof’s water-shedding integrity. For coastal or highly corrosive environments, stainless steel fasteners are strongly recommended.
Thermal Expansion Allowance: Metal roofing expands and contracts with temperature changes. Fasteners should not be over-tightened; the EPDM washer should be compressed but not deformed. For continuous runs exceeding 30 meters, expansion joints or sliding clip systems should be considered.
Side Lap Orientation: Sheets should be laid with the side lap facing away from the prevailing wind direction to minimize wind-driven rain penetration. A recommended minimum side lap of one full rib is standard practice.
Cutting: Where on-site cutting is required, power shears or nibblers are recommended over abrasive cutting discs, which generate heat and can damage the metallic coating and paint finish at cut edges. All cut edges should be touched up with zinc-rich paint or the manufacturer’s approved touch-up system.
Walkability: When foot traffic is necessary during installation or maintenance, workers should step only on the pan areas directly above purlin supports and wear soft-soled footwear to prevent coating damage.
IBR roof sheeting is designed for low-maintenance long-term performance. Periodic inspections are suggested to identify and address loose fasteners, debris accumulation in gutters, and any localized coating damage. For galvanized finishes in aggressive environments, a maintenance repaint cycle of approximately 5-7 years with a suitable metal roof coating system can significantly extend service life. Zincalume and factory-coated products typically require less frequent maintenance intervention.
A: Standard specifications typically carry an MOQ of 5-10 metric tons per size/thickness combination. For custom lengths or non-standard coating specifications, higher MOQs may apply due to mill setup requirements. BOMIS recommends contacting our sales team with your project specifications to receive a tailored quotation that accounts for your volume requirements.
A: Yes. BOMIS offers custom-cut lengths within the 1.5 m to 14 m range, allowing project-specific optimization that reduces on-site cutting and material waste. Length tolerances of -0/+5 mm are maintained for all standard-range custom lengths.
A: IBR features a deeper trapezoidal rib profile compared to traditional sinusoidal corrugated sheets. This geometry provides approximately 30-40% greater spanning capability, allowing wider purlin spacing and fewer structural supports. The effective coverage width (686 mm) and rib height also differ from corrugated profiles, so direct substitution without structural review is not recommended.
A: For coastal installations (within 1-5 km of saltwater), Zincalume or PVDF color-coated substrates are strongly recommended. The aluminum component in Zincalume’s alloy coating provides enhanced resistance to chloride-induced corrosion compared to standard galvanized zinc coatings. For severe marine exposure, a minimum Z275 coating weight or equivalent should be specified.
A: Standard-grade IBR sheeting in common specifications is typically available within 2-4 weeks from order confirmation. Custom color coatings, non-standard thicknesses, or specialized packaging requirements may extend lead times to 6-8 weeks. For large-volume contracts, BOMIS recommends engaging our procurement team during the project planning phase to secure production slot allocation.
A: Standard export packaging consists of multi-layer protection: an inner vapor-phase corrosion inhibitor (VCI) film, intermediate cushioning layers, and a durable weather-resistant outer wrap with steel edge protectors. Sheets are strapped to wooden pallets or steel stillage frames. Custom packaging configurations — including individual sheet interleaving and desiccant inclusion — are available for long-distance maritime shipments to high-humidity destinations.
