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Install Composite Decking: Part 2

Composite Decking

Welcome to part two of Lowe’s How to Install Composite Decking project. Here you’ll learn how to add the railings, attach a fascia board and secure new lattice. You’ll soon be ready to enjoy your renewed deck.

Preparation for Your Composite Decking Project

Wood Samples

Composite materials don’t splinter or contain knots and are easy to maintain. In addition, composite is available in several styles and colors to enhance the beauty of your deck. If you have questions about selection or installation, ask a Lowe’s associate for help. In preparation:

Contact your local building department and homeowner’s association, if any, for guidelines and requirements on replacing materials on an existing deck.

Review How to Install Composite Decking: Part 1 for instructions on replacing wood deck components with composite materials. Specifically, it covered installation of new composite posts and decking. The following instructions continue the project with installation of railings and trim.

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 1 ¼-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. Check your local building code for specific hardware requirements.

Before beginning any excavation, check for underground utilities. Call the North America One Call Referral Service at 1-888-258-0808 (or just dial 811) for a national directory of utility companies.

Installing Rails and Balusters

Installing Composite Decking Rails

With the decking and posts in place, you can install the railing system. The top and bottom rails allow the balusters to face either toward or away from the deck depending on which way you prefer.

Step 1

Measure the distance between the two posts.

Step 2

Cut the top and bottom rails to fit between the posts.

Wear a dust mask when cutting composite materials.

Step 3

Cut two temporary bottom-rail supports from scrap wood. They should be the same height, 2 inches to 4 inches, which will be the distance the bottom rail will be raised above the decking. This is called the toe sweep.

Step 4

Place the temporary supports next to the posts and set the bottom rail on top of them.

Step 5

Place a baluster against a post, resting on the bottom rail, and center it on the post.

Step 6

Attach the baluster to the posts with two screws at each end and three additional screws evenly spaced between the ends.

Step 7

Attach another baluster to the inside of the opposite post in the same manner.

Step 8

Secure the bottom rail to these balusters with two screws. Countersink the screw heads and tap with a hammer for a smooth look.

Step 9

Set the top rail on the balusters and secure the screws just as you did with the bottom rail. Also, drill two holes angled through the top into each post and secure with screws.

Step 10

Place a support block (called a crush block) every 2 feet between the decking and bottom rail, then fasten each with a screw down through the rail and into the block.

Step 11

Calculate the number of balusters needed and the spacing between them.

  • Measure the distance (in inches) between the inside of the starter balusters. Round to the nearest whole number.
  • Divide that distance by 5 inches to get the number of balusters needed.
  • Multiply the number of balusters by 1 ½ inches (the width of the balusters), then subtract that number from the total distance. This will give you the remaining space.
  • Add 1 to the number of balusters.
  • Now divide the remaining space by your answer from Step 4 to determine baluster spacing.
Building codes for decks often define safe spacing between balusters and stairs for safety of children.

Step 12

Cut two spacer blocks from scrap material. Cut them the width of the spacing between balusters.

Step 13

Use the spacer blocks to set the baluster in position.

Step 14

Attach the baluster with a screw through the bottom and top rail.

Step 15

Repeat the spacing and installation of balusters until the railing is complete.

Step 16

Assemble the other railings. Remember to use a hammer to help hide the screw heads.

Installing Stair Railings

Installing Stair Railings

Stair railings and balusters are installed in the same manner as others on a deck, except that the rail ends must be cut to the stairway angle. Following are instructions for determining that angle and installing stair railings and balusters.

Step 1

Lay a top and bottom rail along the edges of the step and against the posts.

Step 2

Mark the rails on the inside faces of the two upright posts.

Step 3

Cut each rail along the mark lines.

Step 4

Position the bottom rail ½ inch above the edges of the steps or as directed by local building codes. Use scrap material as temporary support blocks.

Building codes for decks often define safe spacing between balusters and stairs for safety of children.

Step 5

Cut the ends of balusters at the same angle as the rail ends.

Step 6

Install the rails and balusters following the previous instructions.

Finishing the Deck


Step 1

Install the post caps. Many simply snap into place; others require construction adhesive or screws. Follow the manufacturer’s instructions for installation.

Step 2

You can cover bolt holes from old posts using 2-inch-by-6-inch fascia or trim boards. For best results, use composite boards about 2 inches narrower than the rim joist.

Position the boards flush with the top of the decking and clamp them in place. You may need assistance setting the boards in place.

Drill pilot holes for screws, and attach with screws.

Use a similar method to finish the stairs as well.

  • Hold the composite fascia board in place.
  • Mark the cut out of the stairs.
  • Cut the board.
  • Attach with screws.

Step 3

Install vinyl lattice.

  • Measure and cut the lattice sheets to fit the selected location(s).
  • Add lattice trim for a cleaner look.
  • Place the cut lattice in position.
  • Secure the lattice to the posts and other frame members with lattice screws.

Step 4

Add new deck furniture and perimeter landscaping to finish off the job. Now it’s time to enjoy your efforts and share them with family and friends on your newly remodeled deck.