How to Convert an Existing Wood Deck to a Composite Deck

Composite decks last longer and are low maintenance.

Wood decking materials are high maintenance, requiring resealing every year and eventually needing replacement. Composite materials are more expensive than wood, but will last longer and do not require any maintenance other than an occasional cleaning. The environmentally friendly composite decking material is comprised of recycled wood and plastics. Composite materials will not warp as they are impervious to termites and other wood-eating insects. Composite decking materials contain no chemicals, making them safe to walk on barefoot and for children to play on.

Things You'll Need

• Screwdriver
• Drill driver
• Pry bar
• Vice grips
• Joist hangers
• Nails
• Screws
• Hammer
• Circular saw
• Composite deck boards
• Wood shims

Instructions

1. Use a screwdriver, or a drill driver with a screwdriver bit, to remove the deck screws out of the old decking boards. If the screws are rusty and break when you are trying to remove them, use a pry bar to pry up the deck boards. Use vice grips to remove any remnants of broken screws from the joists after removal of all the old deck boards.

2. Inspect the joists and posts of the old deck framing for rot and other damage. Check the distance between the floor joists. Composite deck boards require that the joists be 16 inches apart. Use joist hangers to add additional joists if the existing joists are spaced further apart. Attach joist hangers to the perimeter framing with nails or screws. Cut the new joists to length and tap with a hammer to slide it down into the joist hanger. Use nails or screws to secure the new joist into place by driving screws through the joist hanger into the joist.

3. Cut each decking board using a circular saw to ensure that the end falls in the center of the joists. For a stronger deck, stagger the butt joints. Lay several rows of deck boards out on the joists using shims to keep the gap between the deck boards uniform. Most composite boards are spaced with a 1/4-inch opening between the long sides of the deck boards to allow water to drain off the deck. Plastic spacers can be purchased from the deck supplier or you can make your own from plywood. Use a drill driver to drive galvanized or stainless steel screws into the joist. Dependent upon the width of the composite deck boards used, use two to three screws at each end of the deck boards and into each joist. Remove the spacers after the screws are in place.

4. Continue laying out the deck boards and driving the screws until the deck is completed. Trim the ends of any of the deck boards that are uneven on the ends.

Tips & Warnings

• Wear safety glasses when cutting composite deck boards.

References

• Washington State University Extension: Wood Plastic Composites
• University of California, Berkeley: Decks Fire Safe or Not?
• Ron Hazelton: How to Replace an Old Deck with Composite Decking