Sourcing steel roof screws from a trusted manufacturer? Sinsun offers self-drilling Tek screws with EPDM washers for metal-to-wood and metal-to-steel applications. View size chart, coatings, and bulk pricing.
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| Diameter | Length Range | Drill Point Type | Head Style | Washer | Coating Options | Substrate |
| #8 | 3/4″ – 1-1/2″ | Sharp / TEK 2 | Pan / Hex Washer | Bonded EPDM | Zinc-plated, Class 4, Black | Wood, thin steel |
| #9 | 1″ – 2″ | Sharp / TEK 2 | Pan / Hex Washer | Bonded EPDM | Zinc-plated, Class 4, Black, Ruspert | Wood, light-gauge steel |
| #10 | 1″ – 3″ | Sharp / TEK 3 | Hex Washer / Pan | Bonded EPDM | Class 4, Ruspert, 304SS, 316SS | Wood, 14–22 gauge steel |
| #12 | 1-1/2″ – 4″ | TEK 3 / TEK 4 | Hex Washer | Bonded EPDM | Class 4, Ruspert, 304SS, 316SS | 12–20 gauge steel |
| #14 | 2″ – 6″ | TEK 4 / TEK 5 | Hex Washer | Bonded EPDM | Class 4, Ruspert | 10–16 gauge steel |
| 4.8mm | 25mm – 150mm | TEK 3 / TEK 4 / Type 17 | Hex Washer | Bonded EPDM | Zinc-plated, Class 4, Ruspert, Black | Wood, 0.5–3.0mm steel |
| 5.5mm | 35mm – 200mm | TEK 4 / TEK 5 | Hex Washer | Bonded EPDM | Class 4, Ruspert, 304SS | 1.5–5.0mm steel |
| 6.3mm | 50mm – 250mm | TEK 5 / TEK 6 | Hex Washer | Bonded EPDM | Class 4, Ruspert, 316SS | 3.0–6.0mm heavy steel |
Homeowners increasingly gravitate toward metal roofs for their toughness and energy efficiency. Residential metal roofs are typically fastened to wood purlins or plywood sheathing with #9 or #10 sharp-point screws with hex washer heads and EPDM washers. Pull-out values can only be achieved when the screw passes through the metal panel and at least 1 inch into solid wood. Standard spacing: 12 to 24 in. Along panel ribs and overlaps, depending on wind load requirements.
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Agricultural buildings require fasteners resistant to manure gases, humidity and temperature changes. We usually use a number of four galvanised or Ruspert coated steel roofing screws. Heavy-gauge steel panels are commonly fastened to steel purlins with self-drilling TEK 3 or TEK 4 screws. Lengths vary but are usually 2" to 4" depending on the panel profile and insulation thickness. The EPDM washer seal is crucial in hay barns and livestock facilities, as dust and moisture entering around the fasteners leads to early corrosion of the panels.
Contact usFasteners used in office buildings, retail centers and institutional buildings must meet more demanding building codes and carry longer warranty periods. For commercial projects, self-drilling screws require documented salt spray test results, typically 1,000 hours minimum for coastal locations. Stainless steel is a common specification for food processing plants and chemical plants where corrosion due to cleaning agents or chemical contact is a factor. Standing seams and clips are also used in commercial roofing. They need special low profile pancake head clips or screws to attach the clips to the structural deck.
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Steel roof screws attach racking systems for ground-mounted and roof-mounted solar arrays to metal roofs. You will need TEK 5 or TEK 6 self-drilling screws to go through the roof panel and into the steel purlins below. The screws should meet both structural shear requirements for solar panels' additional weight and wind loading-standard #12 or #14 diameter with hex washer heads and EPDM sealing washers. These applications require corrosion protection since solar arrays last 25+ years.
Contact usIn markets such as South Africa, Australia and Southeast Asia, IBR and corrugated steel roofing dominate residential and agricultural construction. For these applications steel roof screws will typically have colour matched heads to blend with the panel finish. The drill point has to be able to cope with the light gauge steel profiles commonplace in these areas. Hot dipped galvanisation is the norm to deal with humidity and the occasional salt exposure.
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Whenever extreme temperature changes occur, refrigeration buildings require fasteners able to withstand them without coming loose.Regular screws can back themselves out over time as things expand and contract with heat. It is common for cold storage steel roof screws to have finer threads and modified drill points in order to maintain tension across a wide range of temperatures.EPDM washers must remain flexible at low temperatures – our washers pass testing down to -40°C (-40°F).
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Selecting the Proper TEK Point for Steel Substrates
The TEK number on a self-drilling screw denotes the length and shape of the drill point, which determines the thickness of steel that can be drilled through.
TEK 2: 1.5mm max steel thickness. Perfect for light gauge roofing panels, thin sheet metal and duct work. Residential metal roofs typically have panels attached to 22 to 26 gauge steel.
TEK 3: Maximum steel thickness is 3.0 mm. There are several types of metal roofing points, but this is the most common. This machine works on purlins and structural framing made of 14-20 gauge steel. This is what 90% of our customers order for standard jobs.
TEK 4: Max. Steel thickness is 5.0mm. Required for heavy gauge steel frames, industrial building purlins (10-12 gauge), and solar array mounting structures.
TEK 5 & up. For structural steel up to 6.5 mm+. Commercial, high-rise bridge infrastructure or applications where a panel is directly connected to I-beam flanges.
The drill point will burn out before the screw seats if you choose a small drill point. The screw will just spin without cutting.If the drilling point is too long, there will be a wasted amount of time and the panel will be overdrilled.Match the TEK number to your purlin gauge and test on scrap material before starting the full installation.
Hex Head Washer Driver Tips
All Sinsun steel roof screws have standard 1/4″ hex heads to match the magnetic hex drivers used in production roofing. For high volume installations, we recommend:
Use a magnetic hex driver with a depth-stop collar to avoid over-driving.
When bolting steel to steel, the driver clutch should be set to around 2,000 – 2,500 RPM. Higher speeds can burn out the drill point.
Replace worn hex bits weekly on large projects. Worn bits round out the hex head and make it difficult to extract.
Weathertight seal installation Best Practices
Improper fastener seating is the most common cause of metal roof leaks. The correct sequence is this:
Hold the screw at right angles to the panel, i.e. 90 degrees to the surface. The angled screws deform the washer and create gaps [11†L20-L22].
Drive until the EPDM washer touches the panel surface. It should compress and bulge slightly around the head perimeter. You can see the right amount of compression: the washer should be flattened but not extruding past the edge of the head.
As soon as you see the first sign of tire compression, stop driving. If you notice rubber oozing out beyond the screw head edge, you have overdriven the fastener. Eventually that washer will lose flexibility and crack, leaking [12†L28-L34].
When using ribbed panel profiles, always fasten through the flat of the panel, never through the high ridges, which are difficult to seal.
Roof Panel Spacing Recommendations
Screw spacing recommendations are:
Overlaps and edges of panels: Every 6 to 12 in.
In field areas: 12 to 24 inches depending on panel profile, wind load requirements and local building codes.
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Sinsun’s 316 stainless steel roof screws are our top seller for coastal projects. In Chile’s salty northern regions, ordinary galvanized screws rust in 2–3 years. Sinsun’s 316 screws look new after 5 years. Customers love the reliable seal and easy installation. Reorders keep coming monthly.”
“We use Sinsun wood-to-metal screws for farm buildings and barns. The sharp point drives through metal panels and timber purlins without pre-drilling. They hold tight in high-wind Highveld areas. We’ve used cheaper screws before—they loosen or leak within a year. Sinsun’s screws save us time and callbacks.”
A: They go by several names: metal roofing screws, Tek screws, self-drilling roofing screws, self-tapping metal roofing screws, or simply roof screws. “Tek” is a brand name that became generic for self-drilling screws with a drill point tip.
A: Self-tapping screws threads cut into an existing pilot hole but cannot create the hole themselves. Self-drilling screws (Tek screws) have a built-in drill point that creates the hole and cuts threads in one operation. For metal roofing into steel purlins, you want self-drilling.
A: Not when you use self-drilling screws (Tek screws) with the correct TEK point for your steel thickness. The drill point cuts the hole and taps threads in one motion. For metal-to-wood applications, the sharp point of a Type 17 screw pierces the metal and self-taps into wood without pre-drilling.
A: For metal panels fastened to wood purlins (typical residential), use #9 or #10 diameter sharp-point screws, length 1-1/2″ to 2-1/2″. For metal-to-steel fastening (commercial, agricultural), use #12 or #14 diameter self-drilling screws with TEK 3 or TEK 4 points, length 2″ to 4″.
A: Yes, 304 and 316 stainless are compatible with galvanized panels and won’t cause galvanic corrosion in most environments. For marine applications, 316 is required due to higher chloride resistance.
A: Match the TEK number to your material thickness. TEK 2 for steel up to 1.5mm, TEK 3 up to 3.0mm, TEK 4 up to 5.0mm, TEK 5 up to 6.5mm. If the drill point burns out before the screw seats, your point is too short for the steel thickness.
A: Class 4 refers to a thick zinc coating (8μm+) providing standard exterior corrosion resistance. Ruspert is a premium multi-layer system (zinc + aluminum + ceramic topcoat) delivering 1,000+ hours of salt spray resistance—roughly 10x better than standard zinc. Spec Ruspert for coastal, high-humidity, or industrial environments.
A: Yes. For roof-mounted solar arrays, use #12 or #14 self-drilling screws with TEK appropriate for your purlin thickness. The screws must meet structural shear requirements for added weight and wind loading. Many installers specify TEK 5 points for heavy-gauge structural steel.
A: Most screws are labeled by total length in inches (1-1/2″, 2″, 3″, etc.) or millimeters (50mm, 75mm, etc.). Helpful rule of thumb: Take a screw length that equals the combined thickness of your metal panel, purlin, and required penetration (1″ for wood, 3 thread pitches for steel).
A: Yes. We manufacture steel roof screws with colored heads in RAL codes that match common roofing profiles—black, white, gray, brown, red, and green. The color is a baked polyester coating over a corrosion-resistant zinc base. Minimum factory order quantities apply for custom color matches.
A: Proper torque control on your driver is the answer. Drive until the EPDM washer just contacts and begins to compress—not until it squeezes out past the screw head. Also, fasten through panel flats, not valleys. If you see displaced rubber around the washer’s edge after driving, that screw is over-torqued and will eventually leak.
A: Shear and pull-out values vary by substrate thickness and material. For #12 self-drilling screws into 14-gauge steel (2.0mm), typical pull-out exceeds 300 lbs per screw under static testing. Always check local building codes for specific engineered values on structural applications.
A: Yes. We offer certified fasteners with ETA documentation per EAD 330046–01–0602 for roofing applications and ICC-ES reports for the North American market. Contact us with your specific certification requirements, and we can supply the relevant documentation.
A: Absolutely. We manufacture and ship direct to wholesale distributors, roofing contractors, and industrial buyers worldwide. Tell me your estimated annual consumption—head style, diameter, length, TEK point, coating preference—and I’ll prepare a tiered pricing schedule that beats whatever your current supplier is offering.
A: Always. We ship sample packs of steel roof screws in your specified size and finish. Run them through your nailers, test them on your materials, inspect the EPDM seating and coating durability. Quality verification is the only way to buy fasteners with confidence.
If you’re a metal roofing contractor, an agricultural builder, or a wholesale distributor, shoot me your specs. I’ll put together a bulk quote on Sinsun steel roof screws—consistent hardness, reliable TEK points, and corrosion protection that actually lasts. Direct from our factory to your job site.
Get a Quick QouteWhether you need small batches for a residential project or bulk orders for a large industrial job, Sinsun has you covered. We understand high-end projects demand high-quality fasteners, so we never cut corners. Contact our team now for a competitive quote—we’ll help you pick the right screws, deliver on time, and ensure your roof stays secure for decades. No rust, no leaks, just reliable performance you can trust.
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