How to Install Fascia Boards for a Deck

Before you begin any DIY project, make sure to wear the appropriate personal safety equipment. Eye protection, ear protection, gloves, long pants, a long-sleeved shirt, and reinforced toe shoes are recommended. Always make sure that you have a first aid kit nearby. For any home project, be certain to follow local code and permitting requirements. 

Through spacer installation, you can ensure the fascia material is flush with the top of your decking to maintain safety and visual appeal. Spacer installation also allows for airflow between the fascia material and the rim joist of the deck frame, which is critical to the longevity of your materials. It's equally important in preventing debris and water from collecting between the fascia and the rim of the deck.

Step 1: Place Spacers

To install Trex® Fascia flush with the top of your decking, use spacers attached to the frame and placed at the correct intervals for fastener attachment. 

The spacer material should be rot-resistant, using materials such as treated lumber, PVC, or composite. Spacers should be approximately 3/16” to ¼” thick, minimum 1” wide, and cut to the length of the rim joist of the deck. The spacer in this project was 3/16” thick, 1” wide, and 7 ¼” long. Spacer material can be purchased in long lengths and cut to shorter lengths or made on-site to your specifications.

Step 2: Install Spacers

Install the spacers at 9” apart from the center of each spacer. The maximum spacing between the fascia fasteners is 18”. 

Step 3: Drill Hole in Spacers

Using a 3/16” wood pre-drill bit, drill one hole in the middle of the spacer. Place a single fastener in the pre-drilled hole of the spacer and tighten until the fastener indents into the spacer.  Do not over-tighten as it could split the spacer. 

Step 4: Determine Fascia Fastener Placement

Measure and mark every 18” on the fascia to determine where to place the fasteners. Mark 2” down from the top of the fascia for the top fastener.

To determine the placement and how many fasteners are needed see the diagram below or visit our fastener placement guidelines.

Step 5: Decide on Fastener Color or Plug

The fascia fasteners can be color matched, or they can come with a color-matched plug that will hide the fastener once complete.

The color matched fastener should be indented to be flush with the fascia material, creating the illusion of a seamless surface.

The hidden fastener with plug option has the fastener indented deeper to allow room for the plug. Although slightly more complex to install than color-match screws, these fasteners will create the most seamless look for fascia.

To install fascia screws, you'll need to use a specific drill bit designed to create a hole that allows your fastener to be recessed into your fascia board. Creating this specific hole helps your fastener to be flush or indented into the fascia material, depending on whether the fascia screw will have a plug on top or not. You'll need to purchase this drill bit separately from the fastener company before installation. 

Step 6: Pre-Drill Fastener Holes

Place the fascia on a table or sawhorses and pre-drill the holes for the fasteners. 

Refer to our installation guide for an approved list of fasteners for Trex Fascia. 

Clamp a small piece of 2X4 to the guardrail post on top of the decking. The 2X4 should overhang the edge of the deck by at least 1”. Clamp multiple 2X4’s so that the fascia has a stopping point all along the top of the deck.

Step 7: Clamp Fascia

Place the fascia against the rim joist and tight against the 2X4 blocks clamped on top of the decking. 

Clamp the fascia to the 2X4 blocks. Make sure that the fascia is tight against the rim of the deck. This will keep the fascia flush with the top of the decking.  The clamp will allow working hands free while fastening the fascia.

Step 8: Drill in Fastener

Pre-drill into the hole of the fascia with a 1/8” wood drill bit. Only drill through the depth of the spacer and not into the rim joist of the deck. Then, drill in your fasteners through the fascia and into the rim joist using your pre-drilled hole.

Step 9: Ensure Fascia is Flush With Deck

Hold a scrap 2x4 or a speed square on top of the decking and fascia to ensure the fascia is flush with the top of the decking. The fascia can be raised or lowered if needed as the fasteners are installed. This will ensure that the fascia is flush with the top of the decking the entire length of the deck.

Step 10: Plug Holes

Once all the fasteners have been installed, if applicable, tap the composite deck plugs into the holes on top of the screws.

Refer to our installation guide for gapping requirements on fascia ends. 

Now that you know how to install fascia boards, you can build a professional-looking deck all on your own. If more questions pop up before or as you're building your deck, check out the other lessons available on Trex Academy. Whether it's your first time or you just need a refresher, these how-to guides can help you avoid common mistakes and set up your project for success.