Securing composite decking boards primarily involves using specialized clips or screws designed to create a strong, durable, and often blemish-free surface. For a clean, fastener-free look on the deck surface, the most common method involves using hidden fastening systems.
Key Methods for Securing Composite Decking
To secure a composite deck board, you will typically use either hidden fasteners, which include start/stop clips, or in some instances, face screws. The choice often depends on the specific board type, desired aesthetic, and the area of the deck being fastened.
1. Hidden Fastening Systems (Clips)
Hidden fasteners are the preferred method for most composite decking installations, as they provide a smooth, unblemished surface by attaching the boards from the side grooves.
- Start/Stop Clips: As per installation guidelines, to secure the board, place the start/stop clips in the groove and attach the clips with screws. These specialized clips are designed for the first and last boards of a decking run, or for areas where a traditional grooved clip cannot be engaged from the side. They typically fasten directly into the joist below, securing the edge of the board.
- Mid-Board Grooved Clips: For the majority of the deck boards, specific grooved clips (often T-clips or similar systems) slide into the pre-grooved edges of the composite boards. These clips are then screwed into the joists, effectively securing two adjacent boards simultaneously while maintaining consistent spacing.
Benefits of Hidden Fasteners:
- Clean Aesthetic: No visible screws on the deck surface.
- Consistent Spacing: Clips automatically create uniform gaps between boards for proper drainage and expansion.
- Easier Board Replacement: Individual boards can sometimes be removed or replaced with less hassle.
2. Face Screwing
While less common for the main deck surface due to visible fasteners, face screwing is sometimes necessary for specific applications.
- Perimeter Boards: The very first or last boards against a house or railing might be face-screwed if they don't have grooves or if a hidden clip system isn't suitable for that edge.
- Stairs and Risers: These areas often require the direct, strong hold of face screws for safety and stability.
- Picture Frame Boards: Boards used to create a "picture frame" border around the deck often require face screws, typically color-matched to the decking for a seamless look.
Tips for Face Screwing:
- Always use composite deck screws designed to prevent mushrooming or dimpling of the deck surface.
- Pre-drilling may be required, especially for dense composite materials, to prevent cracking or splitting.
- Counter-sink screws slightly below the surface for a cleaner finish.
Trimming and Finishing Composite Decking
Proper trimming is essential for a professional finish and to accommodate skirting or fascia.
- Cutting Deck Boards to Length: To trim the deck boards to length, snap a chalk line along the end joist and cut along the line with a circular saw. Ensure the saw blade is clean and sharp for a smooth cut.
- Overhang for Skirting: Leave a 1-1/4-inch overhang if you're installing skirting. This overhang provides the necessary support and clearance for attaching fascia or skirting boards neatly below the deck surface, creating a finished look that hides the substructure.
Comparative Overview of Fastening Methods
| Fastening Method | Description | Pros | Cons | Ideal Use Case |
|---|---|---|---|---|
| Hidden Clips | Clips fit into board grooves, screw into joists. Includes start/stop clips. | Invisible fasteners, consistent spacing | Can be slower to install, specific tools needed | Main deck surface, modern aesthetic |
| Face Screwing | Screws driven directly through the board surface into the joist. | Strong hold, direct attachment | Visible fasteners, potential for "mushrooming" | Stair treads, perimeter boards, picture frames |
Best Practices for Securing Composite Decking
- Follow Manufacturer Guidelines: Always adhere strictly to the composite decking manufacturer's specific installation instructions. Each brand may have unique requirements for fastener types, spacing, and installation methods.
- Proper Joist Spacing: Ensure your deck joists are spaced correctly (typically 12" or 16" on center) to provide adequate support for the decking and fastener attachment.
- Allow for Expansion/Contraction: Composite decking expands and contracts with temperature changes. Hidden clip systems are designed to accommodate this movement, but it's crucial to ensure proper gapping.
- Use the Right Tools: Employ a high-quality drill, the correct drive bits for your fasteners, and a good circular saw for cutting.
By carefully selecting the appropriate fastening method and following best practices, you can ensure your composite deck is secure, stable, and visually appealing for years to come.
