If your deck is looking weathered and worn, you can replace components with composite materials without a complete rebuild. Composite doesn’t splinter or have knots and it’s low-maintenance. This is the first installment in a two-part series on How to Install Composite Decking that shows you how to update an old deck using composite materials. The second part will guide you through installing new composite railings, balusters and post caps.
Use this checklist when you go to the store and purchase your items.
Composite materials are manufactured in a variety of colors and styles. If your deck is strong and structurally sound, you can remove all the treated lumber materials and leave the framework intact. The following will guide you through installing composite materials to enhance the look of your deck.
Contact your local building department and homeowner’s association, if any, for guidelines and requirements on replacing materials on an existing deck, including specific hardware requirements.
Read and follow the manufacturer’s instructions for all materials and tools you select for this job.
Many deck material manufacturers recommend ½-inch carriage bolts and nuts with 1¼-inch flat washers; the length depends on the thickness of framing members they must connect, typically 6-inch or 8-inch bolts. Decking screws are often 2 ¼ inches #7 stainless steel or coated square-drive.
Use wrenches and pry bars, as needed, to remove fasteners and hardware attaching the old decking materials to the deck framing. Start with the lattice skirting (if any), then remove the railings, then the decking. Depending on how the deck is constructed and what you're replacing, you may have to remove the posts after the decking.
Once you have removed the old material, visually inspect the framework under the deck for loose connectors, broken posts and wood condition.
The posts will be attached to the inside of the frame with treated lumber bracing and carriage bolts. The bottom of the post will be flush with the bottom of the frame.
Measure the distance between two corner posts and divide by the distance allowed between posts (typically, 6 feet or 72 inches; check the manufacturer’s instructions).
Calculate the number of posts needed by rounding up to the nearest whole number, then subtracting 1. For example, if the distance between two corner posts is 18 feet, divide by 6 feet to get 3, then subtract 1 post for a total of 2 posts.
Mark the position of the post(s) on the deck frame.
Calculate the height of the post(s).
Cut the post(s) to the required height.
Attach the first post to the inside of the rim joist (and end joists) with carriage bolts.
Lay the decking boards on the joists to create a work surface. Start at the rim joist and work toward the house.
Position the first board as needed for installation along the rim joist. You may need to use a jig saw to cut the plank to fit around the posts.
Attach the decking board to each joist with two screws, about 1 inch from edges and ½ inch or more from board ends to prevent splitting.
Continue attaching decking boards end to end to complete the first row along the rim joist.
Place the first board of the second row against the first row. Insert a spacer tool or another tool, like a carpenter’s pencil, between the two boards to ensure a ¼-inch gap between the planks for drainage.
Attach the second row as you did the first, staggering joints on joists.
Continue attaching the decking boards.
If the decking boards hang over the deck frame edges, snap a chalk line over the top of the end joists and cut with a saw.
Install the base cove moulding over the posts.