Poly-fast™ Polycarbonate Roofing Screw – For Metal Battens

POLY-FAST™ – CREST FIXING Polycarbonate Roofing Screws & Fasteners

Introducing POLY-FAST™ polycarbonate roofing screws & fasteners. Due to the high Coefficient of Linear Thermal Expansion (CLTE) of polycarbonate, 65~70 x 10^–6 m/k, the rate of expansion due to thermal changes must be considered when calculating the size required, and enough room must be left for these changes during installation.

A 3-meter-long sheet of polycarbonate for example will expand by approximately 2.1mm for each 10°C temperature increase. A 5-meter-long sheet restrained at one end by being butted up against a brick wall can have its free end move by over 10mm in the course of a day with a 30°C temperature rise.

Before the introduction of fasteners dedicated to fixing thermoplastics, and when metal-fixing hex washer screws were still used, fixing any plastic sheets required at least 2 steps. First, pre-drilling an expansion hole that is approx. 2 times the diameter of the screw using a standard drill bit, which is followed by screwing down the metal roofing screw.

More often than not, builders will skip the first step and drill through the metal roofing screw directly, which is like a ticking time bomb waiting to explode, because sooner or later, the sheets are bound to deform, craze, crack, and break all the way through.

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The Advantages of VULCAN Polycarbonate Roofing Screws

Developed through a collaboration between VULCAN Plastics and BDN Fasteners, POLY-FAST™ polycarbonate roofing screws are designed to deliver a hassle-free, fail-safe fixing solution for plastic roofing systems. 

With user-friendly installation and reliable long-term performance, POLY-FAST™ is one of the easiest and most dependable skylight fixing fasteners available on the market. Below are the key advantages of polycarbonate roofing screws:

Designed for Polycarbonate Roofing Profiles

POLY-FAST™ Crest Fixing Fasteners are suitable for all types of plastic glazing materials and are especially effective as polycarbonate roofing screws. The screw length is precisely engineered to match the crest height of VULCAN ROMA and GRECA profiles, ensuring secure and stable fixing without compromising the sheet structure.

Fail-Safe Thermal Expansion Hole System

When used together with the Thermal Expansion Hole Cutter, a nominal 11 mm expansion hole is created during installation. This allows polycarbonate sheets to expand and contract naturally with temperature changes, reducing the risk of stress cracking or material deformation over time.

Depth Stop Knurls Prevent Over-Driving

The Depth Stop Knurls on the Thermal Expansion Hole Cutter act as a built-in stopper. Once the cutter contacts the purlins, it automatically stops at the correct height, preventing screw over-run or over-driving. This ensures a perfect seal around the enlarged hole without deforming the corrugations.

Superior Weatherproof EPDM Washer

A large domed EPDM weatherseal washer, featuring dual concentric sealing ribs on the underside, completes the system. It fully covers the expansion hole while providing excellent resistance to wind uplift and harsh weather conditions, delivering long-term durability and superior weather protection.

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Common Questions About Polycarbonate Roofing Screws

Q1. What screws do you use for polycarbonate?

Polycarbonate should be fixed using specially designed polycarbonate roofing screws, not standard metal or wood screws.

These screws are engineered to accommodate thermal expansion and typically include features such as a larger shank diameter, controlled fixing depth, and an EPDM washer to ensure a watertight seal without stressing the sheet.

Q2. Can you screw through polycarbonate?

Yes, you can screw through polycarbonate, but it must be done correctly. Screws should always be installed through pre-drilled expansion holes that are larger than the screw diameter. This allows the sheet to expand and contract with temperature changes, preventing cracking, buckling, or long-term damage.

Q3. What kind of screws for plastic roofing?

Plastic roofing materials such as polycarbonate or PVC require roofing screws specifically designed for plastic glazing. These screws typically feature corrosion-resistant materials, controlled fixing systems, and weatherproof washers. 

Using generic screws can lead to leaks, sheet deformation, or premature failure.

Q4. What screws to use for corrugated roofing?

For corrugated roofing, the correct choice is crest-fixing roofing screws designed to match the profile height of the corrugation.

The screw length must be sufficient to pass through the crest and securely fit into the purlin, while the washer and sealing system must protect against water ingress and wind uplift.

Q5. Do you need to pre-drill polycarbonate roofing?

Yes, pre-drilling is essential for polycarbonate roofing. Pre-drilled holes should be oversized to allow for thermal movement. This step is critical to avoid stress cracking, especially in outdoor applications where temperature fluctuations are significant. 

Using a dedicated thermal expansion hole cutter helps ensure consistent hole size and correct fixing depth.

 

Recommend reading:

Corrugated Roof Screws & Polycarbonate Fixing Fasteners

Polycarbonate Roof Colors | Tips on making the correct choices

Installing Polycarbonate Roofing | Preparations prior to fixing Polycarbonate

Polycarbonate Sheet Screws and Fixings