Hidden fasteners are to a deck what blind nails are to a hardwood floor.

How to Fasten Composite Decking

by Chris Deziel

Composite decking has been on the market since the 1990s, and if used correctly, it can outlast wood decking by many years. The original product was an amalgam of recycled wood chips and plastic, although more contemporary versions combine bamboo with plastic or include an extra waterproofing coating. Composite decking handles much like wood, although you can't sand it. It accepts screws and nails, but the best way to attach it to the deck frame is to use a hidden fastener system. To do so, you need boards with grooves into which to hook the fasteners.

Using Screws

Drive 3-inch decking screws in pairs about an inch from either edge of the board with a drill and a No.2 Phillips bit.

Align the screws by using a ruler to extend the line made by the pair on the previous board to the board you're attaching. Drive both screws on the line.

Sink the screw heads about 1/8 inch below the surface of the boards. Sinking them deeper may allow moisture to seep into the core of the material and swell the wood chips, leading to discoloration and mold.

Using Hidden Fasteners

Screw a special start fastener to the rim joist aligned with the midpoint of every regular joist. Leave the screws partially out and hook the front edge of the first row of boards into the fasteners.

Connect a universal fastener, which has two opposing hooks, to the other edge of each board at the intersection of each lateral joist. Partially drive the screw to hold the fastener, then return to the other edge of the board and drive the screws holding the start fasteners all the way.

Install the next row, hooking the front edges of those boards into the other sides of the fasteners. Install more fasteners on the back edges and partially drive the screws, then return to the front and drive the screws in the first row of fasteners home.

Install all the decking boards in the same way except for those in the last row. For those, you need stop fasteners, which are similar to the start ones. Sink the screws all the way as you install these fasteners.

Items you will need

  • 3-inch decking screws
  • Drill
  • No. 2 Phillips bit
  • Hidden fasteners and screws


  • Avoid using nails with composite decking. You may have trouble sinking the heads, and the impact of the hammer can damage the finish. Moreover, nails tend to pull out.
  • Stagger the joints between the ends of the board from row to row to create a random pattern if you have runs longer than your longest deck boards. This prevents unsightly lines stretching across the deck and marring the deck's appearance.
  • If your boards don't have a groove, you can cut one with a router and groove-cutting bit.


  • Don't snap a chalk line to provide a guide for installing screws. Chalk is permanent, and attempting to remove it by sanding will damage the surfaces of composite boards.

About the Author

Chris Deziel has a bachelor's degree in physics and a master's degree in humanities. Besides having an abiding interest in popular science, Deziel has been active in the building and home design trades since 1975. As a landscape builder, he helped establish two gardening companies.

Photo Credits

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