10 COMMON MISTAKES WHEN INSTALLING FIBER CEMENT CORRUGATED SHEETS - AND HOW TO AVOID THEM

Installing fiber cement corrugated roofing sheets is a popular choice for durable and cost-effective roofing in both industrial and residential construction. These sheets are widely used across Asia, Africa, and almost in the world for their strength, resistance to weather, and long-term performance. However, incorrect installation can lead to issues such as water leakage, structural damage, and reduced lifespan.

In this article, we highlight 10 common mistakes during the installation of fiber cement corrugated roofing sheets and provide practical tips on how to avoid them. Whether you're a contractor, project manager, or DIY enthusiast, understanding these pitfalls will help ensure a successful roofing project.

1. Incorrect overlapping of corrugated sheets

Q: How much should fiber cement corrugated sheets overlap?

A: At least one full corrugation side-to-side and 150–200 mm vertically depending on roof pitch.

Why it's a mistake: Improper overlap can lead to water ingress and poor wind resistance.

Solution: Follow manufacturer guidelines strictly for both horizontal and vertical overlaps.

Q: Do I need to cut the corners where four sheets meet?

A: Yes. When four corrugated sheets overlap at one point (called a "four-way lap"), you must cut a small corner from two diagonal sheets.

Why it's necessary: Without trimming, the overlapped corner will be too thick, causing lifting, uneven surfaces, and potential water ingress.

Solution: Use metal shears or an angle grinder to neatly cut a triangle (usually 50–70 mm) from the corner of the top-left and bottom-right sheets to allow them to lay flat.

2. Using the wrong fasteners

Q: Can regular screws or nails be used to install fiber cement roofing?

A: No. Use only galvanized or stainless-steel J-bolts or hook bolts with rubber washers.

Why it's a mistake: Incompatible fasteners can rust or crack the sheets.

Solution: Use purpose-designed roofing bolts with sealing washers to ensure secure and watertight fastening.

3. Drilling holes at the wrong location

Q: Where should holes be drilled in corrugated sheets?

A: Always drill at the crest (top of the corrugation), not the valley.

Why it's a mistake: Drilling in the valley causes water pooling around the fastener, leading to leaks.

Solution: Use a carbide-tipped drill bit and drill at the crest before placing the sheet on the roof.

4. Over-tightening fasteners

Q: What happens if bolts are too tight?

A: It can crack the sheet and deform the roof line.

Why it's a mistake: Over-tightening damages structural integrity.

Solution: Tighten bolts just enough to hold the sheet snugly without compressing the material.

5. Installing on a roof with inadequate slope

Q: What is the recommended slope for fiber cement roofing?

A: Minimum of 10 degrees (17%).

Why it's a mistake: Flat roofs increase the chance of water pooling and leaks.

Solution: Ensure proper pitch to allow rainwater to run off effectively.

6. Walking directly on the sheets

Q: Is it safe to walk on fiber cement sheets during installation?

A: No, unless supported underneath or stepping only on purlins.

Why it's a mistake: Fiber cement is rigid and may crack under body weight.

Solution: Use walk boards or step only where structural support is present.

7. Not pre-drilling holes before fixing

Q: Why should holes be pre-drilled?

A: To prevent cracks during fixing.

Why it's a mistake: Direct drilling can split the sheet or create jagged holes.

Solution: Drill holes 2–3 mm wider than the bolt diameter to allow for expansion.

8. Ignoring wind direction during installation

Q: Does wind direction affect sheet installation?

A: Yes. Sheets should be laid against the prevailing wind.

Why it's a mistake: Laying sheets in the wind direction can allow water and dust to enter overlaps.

Solution: Plan the layout with local climate and wind conditions in mind.

9. Poor handling and transportation

Q: Are fiber cement sheets fragile during transport?

A: Yes. They must be handled with care.

Why it's a mistake: Rough handling can cause invisible micro-cracks.

Solution: Always carry sheets vertically in pairs and avoid dragging them on the ground.

10. Skipping safety procedures and PPE

Q: Is installation of fiber cement sheets hazardous?

A: It can be, especially when cutting or lifting sheets.

Why it's a mistake: Dust from cutting and sharp edges can cause injury.

Solution: Wear gloves, goggles, and dust masks, and use proper lifting techniques.

Conclusion

Avoiding these common installation mistakes is essential for maximizing the performance and longevity of your fiber cement corrugated roofing sheets. Proper technique not only protects your investment but also improves structural safety and weather resistance.

Need expert advice or supply solutions? Contact our team for technical support, product recommendations, and quotations for international shipments. With years of experience delivering high-quality roofing solutions across Asia, Africa, and almost the entire world, we’re here to help you build smarter.