Type 17 roofing screws are a cornerstone component for installing metal roofing and siding. They feature a specialized self-drilling point designed to puncture and seal through tough metal panels with minimal effort, reducing installation time and ensuring a secure, weather-tight fastener. Understanding their differences in material, coating, length, and washer design helps builders choose the right screw for durability, performance, and cost efficiency across residential and commercial projects.
What Are Type 17 Roofing Screws
Type 17 roofing screws are self-drilling fasteners designed for metal roofing and siding installations. The “17” refers to the drill point geometry, which combines a sharp point and threading that allows the screw to cut through metal while forming its own pilot path. This makes separate pilot holes unnecessary in many applications, speeding up work and reducing material handling. Typically equipped with a bonded washer, Type 17 screws create a watertight seal when driven into purlins or structural substrates beneath metal panels.
Key Features To Consider
Drill Point Geometry
The Type 17 point is engineered to penetrate metal cleanly, resisting deflection and reducing stripping. This drill point improves consistency when driving into steel or aluminum panels and helps prevent damage to the panel edge or threads. The result is a reliable seal and lower risk of leaks around fastener heads.
Washer Design And Seal
Most Type 17 screws include a bonded or attached washer made from EPDM or neoprene. The washer distributes load across a broader area, helps seal the fastener, and minimizes water infiltration. Proper washer selection is essential to maintain long-term performance, especially in harsh weather or coastal environments.
Material And Coating
Common materials include carbon steel with zinc coating, stainless steel, and often coated variants such as ceramic or Weathered metal finishes. Stainless steel Type 17 screws excel in corrosive environments but come at a higher cost. For inland residential use, zinc-coated carbon steel often provides an excellent balance of price and durability.
Length And Gauge
Choosing the right length ensures the screw penetrates adequately into the substrate (typically a purlin or framing member) without bottoming out. Common lengths range from 1 inch to 2-1/2 inches, with gauges commonly around #8 or #10. The panel thickness, substrate, and weather exposure dictate the ideal length and gauge for any project.
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Applications And Best Practices
Type 17 screws are versatile for metal roofing, siding, and related structures. They perform well with steel or aluminum panels, including corrugated and standing-seam profiles. When used properly, they provide reliable weather sealing and structural retention across varying climates.
- Metal Roofing: Ideal for attaching roof panels to purlins or rafters in single-skin or insulated roof assemblies.
- Metal Siding: Suitable for wall panels where strong wind resistance and a water-tight seal are essential.
- Coastal Environments: Stainless steel or premium coated variants offer superior corrosion resistance.
- Architectural Panels: Often chosen for appearance and long-term performance in modern metal facades.
Installation Tips For Optimal Performance
Proper technique maximizes the effectiveness and longevity of Type 17 screws. The following practices help ensure a durable, weather-tight installation.
- Driver Type: Use a low-speed impact driver or drill with a bit compatible with the screw head. High speed can strip fastener heads or over-tighten.
- Pre-Inspection: Check panel alignment and substrate condition before driving screws. Ensure purlins or framing are straight and free of debris.
- Torque Control: Tighten to the point where the washer fully contacts the panel surface without deforming the sheet metal. Avoid overtightening, which can crush the washer and compromise seal.
- Sealing Considerations: Confirm the washer is properly seated and intact. Replace any damaged washers to maintain water resistance.
- Spacing: Follow manufacturer guidelines for fastener spacing, especially along panel edges and corners where wind uplift is higher.
Material Choices: Cost, Corrosion, And Longevity
Selecting the right material and coating affects maintenance, warranty coverage, and total cost over the roof’s life. Here is a concise guide to common options.
| Material | Coating | Typical Uses | Pros | Cons |
|---|---|---|---|---|
| Carbon Steel | Zinc-coated | Residential and light commercial metal roofs | Cost-effective; good corrosion resistance with coating | Corrosion risk in coastal or industrial environments without maintenance |
| Stainless Steel | AA or A2 variants | Coastal, high humidity, corrosive environments | Excellent corrosion resistance; long life | Higher upfront cost |
| Aluminum/Alloy | Non-ferrous coatings | Lightweight panels; specific architectural projects | Excellent corrosion resistance; easy to work with | Lower strength than steel; cost varies |
Comparisons With Other Roofing Fasteners
Type 17 screws are one option among metal roofing fasteners. They are typically compared against Type 1 or Type 8 screws, which have different drill points and are used for various substrates. Type 17’s drill-point design generally provides better self-drilling capability in metal panels, reducing the need for pilot holes. However, for certain thick substrates or specific panel profiles, alternative fasteners may be preferred. Consider panel type, substrate thickness, and environmental exposure when selecting between options.
Common Pitfalls And How To Avoid Them
Wrong screw selection or installation mistakes can lead to leaks, panel damage, or premature failure. Key issues include over-tightening, using incorrect length, choosing incompatible coatings for the environment, and skipping proper seal inspection after installation. A careful approach—matching panel thickness, substrate, climate, and corrosion risk—helps ensure the fastener system performs as designed over the roof’s life.
Maintenance And Longevity
Type 17 screws require routine inspection as part of a broader roof maintenance plan. Look for signs of corrosion, loose washers, or damaged heads after severe weather. In coastal or industrial settings, more frequent checks may be necessary. Replacing compromised fasteners promptly maintains roof integrity and prevents leaks or panel movement during high winds.
Buying Guide: How To Choose The Right Type 17 Screw
Selecting the right Type 17 screw involves balancing cost, performance, and environmental conditions. This quick guide helps buyers evaluate options.
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- Environment: Coastal or chemically active environments favor stainless steel or premium coatings.
- Panel Type: Match length to panel thickness and substrate depth to ensure secure fastening without bottoming out.
- Washer Material: Ensure compatibility with panel material to prevent corrosion or seal failure.
- Warranty: Check manufacturer warranties for coating, corrosion resistance, and installation guidelines.
Frequently Asked Questions
Answers to common questions help streamline project planning and procurement.
- Do Type 17 screws require pilot holes? Not typically, thanks to the self-drilling point, but very hard substrates may still benefit from pilot holes.
- Can Type 17 screws be used for roofing over open framing? Yes, when the substrate and panel thickness are compatible with the screw length and thread engagement.
- Are there color-matched screws for architectural accuracy? Many manufacturers offer color-matched coatings to blend with metal panels and improve aesthetics.