“TimberTech capped-composite fascia boards are used to cover the exposed edges of a deck, creating a polished, finished look while protecting the underlying structure.”
Manufactured decking brands like TimberTech have redefined the reliability and versatility of modern decking. From impressive durability to low-maintenance care, manufactured materials offer a wide range of benefits. But to get the most out of innovative products like TimberTech decking, it’s important to move beyond surface-level features and understand the nuances of each material—and the best practices for working with them.
In our TimberTech series, we're joined by Pat Maher, product application manager and head of AZEK University (TimberTech is an outdoor living brand of the AZEK Company). TimberTech is an industry leader in manufactured decking and a longtime Dunn Lumber partner. Pat brings a lifetime of experience in building materials, with 20 years focused specifically on manufactured decking. We’re excited to share his unique and seasoned perspective.
At a glance
TimberTech fascia boards give your deck a clean, finished look, while protecting its structure. In today's episode, Pat discusses best practices for fastening TimberTech capped-composite fascia, proper gapping based on temperature, and smart installation options like picture-framing for a polished result.
Watch the video above, or read a summary of our conversation below.
What are capped-composite fascia boards?
TimberTech capped-composite fascia boards are used to cover the exposed edges of a deck, creating a polished, finished look while protecting the underlying structure. They act as a trim piece that enhances both aesthetics and durability.
Best practices for fastening capped-composite fascia boards
Capped-composite fascia boards are made the same way as other capped-composite materials, with the same core and cap material. This means it’s important to allow for the proper amount of expansion and contraction. TimberTech’s fascia fastening system was specifically designed to address just that.
Here’s how it works: Staying ¾” back from the ends (and 2” from the top and bottom), use a TOPLoc Fascia Bit to pre-drill holes that are slightly wider than the diameter of the screw (TimberTech recommends using TOPLoc Fascia Fasteners for best results). This allows for the board to move when it expands and contracts, and it helps avoid the buckling that happens—known as “oil-canning”—when boards are fastened too tightly and the material expands with nowhere to go. (Review the TimberTech decking and maintenance guide for more about screw placement and other need-to-know information before you get started.)
When fastening, don’t completely torque down the screw. The threads on the TOPLoc Fascia Fastener are a machine thread—they’re designed to let the fascia board hang on your rim board, not pin it tight like a wood screw would. This allows the fascia to move as it expands and contracts.
Gapping requirements based on installation temperature
When installing fascia boards, pay attention to the temperature and follow the same best practices as you would for any other TimberTech board. Here are gapping requirements for all TimberTech boards:
Side-to-side board gapping must be minimum ⅛” to maximum 3/16”.
Allow 3/16” minimum gap where the boarding meets any adjoining structure or post.
Follow these butt joint gapping guidelines for all TimberTech boards:
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32° F and below: 3/16” gap
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33° to 74° F: ⅛” gap
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75° F and above: 1/32” gap
Where to install your fascia
Should you install your fascia over the end of your deck boards, or underneath? You’ve got options.
If you’re installing the fascia underneath your deck boards but have concerns about leaving the core material visible, you can have your paint manufacturer match the color of your deck board with an exterior-grade acrylic latex paint, and then you can paint the ends.
You can also install the fascia board over the end of your deck boards, though it leaves a potential gap between the board and the fascia, making it possible for debris to get stuck in your framing and cause it to rot prematurely.
One elegant way around this is using the picture-frame method, which involves running a square-edge board perpendicular to the rest of the boards of your deck.