Best Metal Screws for Roofing & Construction: What to Know Before You Buy
Best Metal Screws for Roofing & Construction: What to Know Before You Buy
- Roofix
Introduction: Why Metal Screws Matter More Than You Think
In the world of construction, especially roofing and metal fabrication, the smallest components often make the biggest difference. Metal screws may look simple, but their performance can determine the lifespan, safety, and durability of entire roofing systems.
Whether you’re fixing metal sheets, installing structural steel frames, or working with polycarbonate panels, the type of metal screw you use directly affects corrosion resistance, waterproofing, strength, and long-term reliability. And with the vast variety available — from hex head screws to self-drilling screws for metal, choosing the right one can be overwhelming.
This guide is crafted to simplify that decision. With over a decade of experience in roofing and industrial fastening systems, we’ll walk you through the best metal screws for roofing and construction, their types, coatings, use cases, and expert tips to ensure you make the right purchase — the first time.
Types of Metal Screws Used in Roofing & Construction
Understanding the different types of metal screws is the first step in selecting the right fastener. Each type is designed for specific material compatibility, load requirements, and installation methods.
Here’s a breakdown of the most common types:
1. Self-Drilling Metal Screws
Use for: Fixing metal roofing sheets to steel or timber without pre-drilling
Head type: Hex head, wafer head
Common sizes: 12G, 14G — Lengths vary (19mm to 75mm+)
Advantages:
Saves installation time
Drills and taps in one go
Ideal for purlins and metal beams
✅ Popular variation: Point #5 self-drilling screws – Designed for thick steel (up to 12mm)
Explore our Self-Drilling Screws →
2. Stitch Screws / Side Lap Screws
Use for: Fixing side-lap overlaps between roofing sheets
Size range: Typically 19mm–25mm
Coating: Epoxy or Ruspert
Why they matter:
Prevents sheet uplift during high wind
Ensures sheet-to-sheet contact stays sealed
3. Metal-to-Wood Screws
Use for: Fastening metal roofing sheets onto timber battens
Thread type: Full thread for grip in wood
Head type: Hex flange head for strong torque
Coating: Zinc, Epoxy, or Ruspert for corrosion resistance
✅ Pro Tip: Look for screws with anti-split tips when working with dry timber.
4. Wafer Head Screws (for Fiber Cement)
Use for: Fixing fiber cement boards to steel
Design: Wafer head prevents surface damage
Gauge: 14G; Length often 110mm+
Why it’s different: The shallow head sits flush on the board, preventing cracking or uplift.
5. Wing-Tipped Screws for Polycarbonate Sheets
Use for: Fixing polycarbonate sheets to metal or timber
Special feature: Wings cut thermal expansion holes
Washer: Comes with a 26mm EPDM washer
Importance: Prevents sheet cracking due to thermal movement
View Polycarbonate Screws →
6. Colored Screws (Powder-Coated)
Use for: Visible installations where aesthetics matter
Finish: Available in RAL colors or custom tones
Applications: Roofing, facades, cladding, decorative panels
These screws are powder coated over corrosion-resistant treatments like Ruspert or Zinc plating, ensuring both beauty and strength.
Choosing the Right Screw: Coating, Head Type & Corrosion Resistance
While selecting the right type of screw is crucial, your decision isn’t complete without understanding the coating, head type, and material compatibility. These directly affect not just how well the screw performs — but how long it lasts in harsh environments.
Let’s dive deeper into what truly makes a roofing screw reliable and long-lasting.
1. Coatings & Finishes: Why They Matter in Roofing Screws
Your fastener will face heat, rain, wind, pollution, and even salt-laden air in coastal regions. Without proper coating, corrosion will start quickly — leading to failure, leakage, and roof damage.
Here are the most common coatings found on high-performance roofing screws:
| Coating Type | Protection Level | Use Case |
|---|---|---|
| Zinc Plated | Basic | Indoor, dry areas, general metal fixing |
| Epoxy Coated | Medium | Exterior roofing, general corrosion resistance |
| Ruspert Coated | High | Industrial, urban pollution, moderate coastlines |
| Multi-Layer Rust Shield | Very High | High humidity, coastal, chemical zones |
| Stainless Steel | Maximum | Premium installations, chemical industries |
✅ Roofix screws, for example, come with Multi-Layer Rust Shield Coating, offering superior resistance tested to AS3566-2002 Class 3 standards — essential for Indian climate zones ranging from coastal to desert regions.
2. Head Types: Performance & Aesthetic Considerations
The head of a screw is what you see — but also what controls driving speed, torque distribution, and seating pressure. Different head types are used for different purposes:
| Head Type | Best For | Features |
|---|---|---|
| Hex Flange Head | Roofing, timber frames, structural steel | High torque, washer compatible |
| Wafer Head | Fiber cement sheets, facade boards | Sits flush, no surface damage |
| Pan Head | General utility, smaller fixtures | Aesthetic, rounded finish |
| Low Profile Head | Side lap & overlaps | Hidden finish, tight fastening |
✅ Pro Tip: When using screws in visible facades or architectural roofing, choose low-profile or color-matched heads.
3. Understanding Screw Gauge, Length & Threads
Screws aren’t just about the head and coating — the body matters just as much.
a. Screw Gauge: This is the diameter of the screw. Common roofing sizes include:
12G (4.8mm) — Lighter sheets, wood fixing
14G (6.3mm) — Structural fixing, high-strength applications
b. Screw Length:
This depends on what materials you’re fastening through and into. Use this rough rule:
| Material | Recommended Length |
|---|---|
| Metal sheet to timber | 35mm – 55mm |
| Metal sheet to steel | 25mm – 75mm |
| Fiber cement to steel | 100mm – 120mm |
| Polycarbonate sheets | 50mm – 70mm |
✅ Note: Always ensure the screw penetrates the base material by at least 3 full threads for holding power.
c. Thread Type:
Single Thread: Faster driving, suited for timber
Twin Thread: Better grip in thin metals
Fine Thread: For thick steel sections (Purlins/HR beams)
4. Washers & Sealing: Don’t Ignore This Part
A screw’s performance is not complete without the right washer. Washers ensure waterproofing and prevent the screw from digging into the sheet.
Most common:
EPDM Washers – These are UV-stable, flexible rubber washers that compress to form a tight seal around the screw.
| Washer Type | Use Case | Size |
|---|---|---|
| Standard EPDM | General roofing, steel fixing | 16mm–19mm |
| Large EPDM | Polycarbonate sheets | 26mm |
| Color-matched EPDM | Decorative applications | 16mm–19mm |
5. Environmental Factors & Regional Suitability
Based on your geographic location in India, here’s how screw coatings and materials should be chosen:
| Region | Recommended Coating | Screw Type |
|---|---|---|
| Coastal areas | Multi-layer / Ruspert / SS | Stainless steel or Rust Shield screws |
| High humidity zones | Rust Shield / Epoxy | Self-drilling with EPDM washers |
| Dry, desert regions | Zinc-plated or Epoxy | Wood or Stitch screws |
| High wind zones | Structural screws (14G+) | Heavy gauge, correct spacing |
✅ Pro Tip: Use a corrosion resistance standard like AS3566-2002 Class 3 or 4 when choosing screws for industrial and coastal projects.
Buying Guide: How to Choose the Right Metal Screw
Choosing a screw isn’t one-size-fits-all. Here are the most important questions you should ask before buying:
a) What Material Are You Fastening?
Steel to steel ➜ Use self-drilling screws (Point #5) with high corrosion resistance.
Metal sheets to timber ➜ Use wood screws with wide threads and hex heads.
Polycarbonate to any substrate ➜ Use polycarbonate screws with thermal wing tips.
Fiber cement sheets ➜ Use wafer head screws for flush finish and strength.
b) What Are Your Environmental Conditions?
Coastal / humid zone ➜ Prioritize corrosion resistance (Multi-layer Rust Shield / Ruspert).
Urban / industrial area ➜ Use Class 3 coated screws to resist pollution and rain.
Dry or inland zone ➜ Epoxy or zinc-plated screws may be sufficient.
c) What Kind of Load Will the Roof Handle?
For heavy-duty structural roofing, go for 14G screws with high tensile strength.
For side laps or short fixings, use stitch screws (19mm–25mm).
📌 Tip: Always calculate screw spacing based on wind zone and roofing type. Improper spacing leads to uplift, leaks, or entire panel failure.
Related Blog: Self-Drilling Screws: The Ultimate Guide for Industrial, Roofing & Structural Applications →
Pricing & Cost Breakdown :
The price of roofing screws can vary based on:
Material (carbon steel vs stainless steel)
Coating (Rust Shield is costlier than zinc)
Washer quality
Size and application
Average Market Prices (India – 2025 Estimates):
| Screw Type | Estimated Price (Per Piece) |
|---|---|
| Self-drilling screws (14G) | ₹2.00 – ₹3.50 |
| Wood screws (14G) | ₹1.80 – ₹3.20 |
| Polycarbonate screws | ₹3.00 – ₹4.50 |
| Wafer head cement screws | ₹2.50 – ₹4.00 |
| Stainless steel screws | ₹5.00 – ₹8.00 |
✅ Roofix provides high-performance screws with industry-certified coatings, offering value for durability without compromise.
Tool Compatibility: What You Need to Drive Roofing Screws
You can’t install screws effectively without using the right tools — and doing it wrong can strip the screw, damage the sheet, or cause over-driving.
✅ Recommended Tool:
Makita FS2700 or equivalent roofing screw gun
Speed: 0–2500 RPM
Torque control
Magnetic hex bit holders
Compact body with LED light
Explore Tool: Makita FS2700 Drill Machine →
✅ Screw Gun Features to Look For:
| Feature | Why It Matters |
|---|---|
| Adjustable torque | Prevents overdriving or screw stripping |
| Magnetic socket holder | Holds screw firmly during vertical fixing |
| Low vibration motor | Reduces fatigue during long usage |
| 2500 RPM range | Optimized for self-drilling screws |
Screws vs Rivets: Which Is Better for Roofing?
Both fasteners serve different purposes, but when it comes to roofing and construction:
| Feature | Screws | Rivets |
|---|---|---|
| Installation | Easy with power tool | Requires rivet gun |
| Holding strength | Excellent (especially for steel) | Good but less than screws |
| Removal & reusability | Removable and reusable | Not reusable |
| Cost per unit | ₹2.00–₹4.00 | ₹1.00–₹2.50 |
| Sealing ability (with washer) | High – EPDM washer provides seal | Needs additional sealing |
| Flexibility | Many head types/sizes | Limited flexibility |
✅ Conclusion: Screws are more versatile, offer better sealing, and can be removed during maintenance. Roofing screws win in most construction use cases.
Final Checklist: Choosing the Right Metal Screw
Use this quick checklist when finalizing your screw type:
✅ Is your substrate steel, timber, or concrete?
✅ Do you need waterproofing (then use EPDM washers)?
✅ Are you in a coastal / industrial region (need Rust Shield or Ruspert)?
✅ Is your tool compatible with the screw drive (e.g., hex head)?
✅ Have you calculated spacing and quantity based on your structure?
Explore Full Range: Metal Screws by Roofix →
Frequently Asked Questions (FAQs)
The best screws for metal roofing are self-drilling screws with hex heads, EPDM washers, and multi-layer rust-resistant coating. At Roofix, we recommend our Class 3 certified screws for long-term protection and performance.
👉 View Roofing Screws →
Yes — but only if they include high-quality EPDM washers and are properly installed. Roofix uses DEKS TrueBlue EPDM washers that stay flexible and watertight in all conditions.
Most roofing projects use 14G screws ranging from 25mm to 75mm depending on your purlin or frame. Always match screw length to the thickness of the material and substrate.
👉 Learn more on our Roofing Fasteners Page →
We recommend the Makita FS2700 screwdriver or similar, with 2500 RPM, torque control, and a magnetic bit holder. This ensures consistent driving without damaging the screw or sheet.
👉 Check Drill Machine →
No — they are designed with a drill tip that creates its own hole in metal or timber. This saves time and effort.
Final Thoughts
Choosing the right metal screw may seem like a small detail — but it’s the difference between a roof that lasts decades and one that fails in a storm. By understanding types, coatings, applications, and tools, you’re now equipped to make the smartest choice.
Whether you’re securing metal sheets, fixing fiber cement panels, or sealing polycarbonate, Roofix offers fasteners that don’t compromise on strength, durability, or performance.
👉 Need help choosing? Contact Us Now →
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