Face-Fastening PVC Decking: Questions for Your Installer

Why Choose Face-Fastening for PVC Decking?

Face-fastening, despite exposing screw heads, offers distinct advantages for PVC decking projects. It provides a strong, direct connection between the deck board and the substructure, which can be beneficial in applications where boards might experience uplift or heavy foot traffic. For example, perimeter boards, stair treads, or areas around hot tubs and pool surrounds often benefit from the added security of face-fastening.

Some PVC decking profiles are specifically designed for face-fastening, or require it in conjunction with hidden fasteners for certain applications. It's also a common method for securing starter and end boards where hidden fasteners may not be feasible. The method allows for easier removal and reinstallation of individual boards if maintenance or access to the substructure is ever required, compared to some hidden fastening systems.

Approved Fastener Types for PVC Decking

The most critical decision in face-fastening is selecting the correct screws. PVC decking manufacturers specify particular types of screws that are compatible with their products. These are typically coated or stainless steel screws designed to resist corrosion and prevent staining of the decking material. Using non-approved screws can lead to discoloration, fastener failure, or voiding of product warranties.

Commonly specified screws for PVC decking are often color-matched to the deck boards, or designed to be used with a plugging system. These specialized screws are engineered to create a clean hole and hold securely in PVC, which behaves differently from wood or composite materials under stress. Always refer to the specific PVC decking product's installation guide for the exact type, length, and material of approved fasteners.

For example, if you are using TimberTech Azek PVC decking, the manufacturer will specify the exact screws recommended for face-fastening, which may include specific types of stainless steel or coated screws designed to prevent mushrooming or dimpling of the PVC surface.

The Importance of Pilot Holes

Unlike wood, PVC can be more susceptible to cracking or splitting if screws are driven without proper preparation, especially near board ends or edges. Creating pilot holes before driving screws is a crucial step in face-fastening PVC decking. A pilot hole is a pre-drilled hole that guides the screw and reduces the material stress.

The size of the pilot hole is vital. It should be slightly smaller than the screw's major diameter (the widest part of the threads) but large enough to prevent undue stress on the PVC. Too small a pilot hole can still cause splitting, while too large a hole can reduce the screw's holding power. Your installer should consult the decking manufacturer's guidelines for the precise pilot hole diameter recommended for your specific PVC boards and chosen fasteners.

Finishing Touches: Using Plugs for a Clean Look

For projects where a visible screw head is undesirable, but face-fastening is necessary, a plugging system offers an aesthetic solution. This involves using specialized screws that create a countersunk hole, into which a matching PVC plug is inserted. These plugs are often made from the same decking material, offering a near-invisible finish.

Plugging systems require precision. The countersink bit must create a consistent depth and diameter for the plug to fit flush. The plugs themselves are typically installed with a small amount of adhesive to ensure they remain securely in place. While adding an extra step to the installation process, plugs significantly enhance the finished appearance of a face-fastened PVC deck, providing a clean, uninterrupted surface.

Not all PVC decking lines are compatible with every plugging system. Confirm with your installer that the specific decking you've chosen supports a plugging system and that they have experience with its proper installation.

Worked Example: Face-Fastening a Perimeter Board

The installer would first mark the screw locations, drill the pilot holes, then drive the screws, ensuring they are flush or slightly countersunk according to the plugging system's instructions. Finally, matching PVC plugs would be set into each countersunk hole with a small bead of appropriate adhesive, then tapped flush. This method ensures a secure attachment while maintaining a clean appearance for the perimeter of the deck.

Before you order

• Confirm if your chosen PVC decking product requires or allows face-fastening for any part of your project (e.g., perimeter boards, stairs).
• Identify the specific brand and model of approved screws recommended by the decking manufacturer for face-fastening.
• Verify the required pilot hole diameter and depth for these screws.
• Discuss with your installer if a plugging system is desired for a cleaner finish, and confirm its compatibility with your selected PVC decking.
• Ensure your installer has experience with the specific face-fastening and plugging techniques for PVC decking.
• Review the manufacturer's installation guide for any special considerations regarding screw placement (e.g., distance from board edges/ends).

Confirm installation details, approved uses and warranty terms in the current instructions for the exact product and profile. Your installer should verify the substrate, structure and applicable project requirements.

Questions to help you decide

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