“Cortex screws,” “top-down fasteners,” “hidden” or “color-matched” — what does it all mean? It can feel like there’s a lot of deck fastener lingo to keep track of.
Don’t sweat it; we’ve got the fastener guidance you need.
How Fasteners Play Into Your Deck Project
If you’ve decided to build your own deck — or are just interested in learning more about what deck installation options you have — you’ve likely thought at least a little about your deck fasteners.
Knowing which deck fastener to use for your project will depend on:
- The profile of the deck boards you choose.
- Your overall deck design — more complex designs such as patterned inlays may require certain fasteners.
- Other factors, like budget, anticipated labor/installation time, etc.
In this post, we’ll break down a popular type of deck fastener categorized as a hidden fastener: Cortex®.
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What Are Cortex Screws?

Cortex screws fit into the category of hidden fasteners. Cortex fastener systems:
- Include plugs made from the same material as the decking for a seamless final look.
- Feature a special driving tip that automatically drives the screw at the correct depth.
- Feature a high-quality, ACQ-approved, specialty deck screw with a TORX® ttap® drive system.
When to Choose Cortex for Your Project
Within the TimberTech® fastener portfolio, you have two Cortex options, each correlated to your choice of TimberTech decking line. No matter which decking line you choose, however:

Cortex Screws Pair With:
Full-profile TimberTech deck boards
You’ll choose your Cortex fastening system depending on the type of decking — or decking line — you choose.
For our capped polymer deck boards found in the TimberTech AZEK decking line, use Cortex® for AZEK®.
For our capped composite deck boards found in the TimberTech PRO and TimberTech EDGE lines, use Cortex® for PRO® & EDGE®.

Cortex® for AZEK®
Secure, hidden fastening system with collated plugs, designed for TimberTech® AZEK® decking.

Cortex® for PRO & EDGE
Secure hidden fastening system designed for TimberTech PRO® and TimberTech EDGE® decking.
Why Choose Cortex Instead of Other Fasteners?

Cortex screws are classed as hidden fasteners.
If you’re looking for the following, Cortex screws are a good choice for your deck project.
- Ease: Cortex offers an easy top-down installation. For TimberTech AZEK deck boards, no pre-drilling is required.
- Strength: Strongest hidden fastener option offered by TimberTech.
- Speed: Collated plugs with pre-aligned grain pattern provide 50% faster installation.
- Beauty: Capture a polished final look by hiding the screw heads.
Hidden Cortex Fasteners vs. TOPLoc® Color-Matched Fasteners
Because of their similarities — primarily the inclusion of a color-matched element to the fastening system — Cortex fasteners are often considered alongside our TOPLoc for AZEK and TOPLoc for PRO & EDGE fastening systems.
Similarities
Both are top-down fastener systems that offer a polished final product.
Differences
1.) Fastener Type

Cortex Screws
Hidden fasteners.

TOPLoc Fasteners
Color-matched fasteners.
2.) Compatibility

Cortex Screws
Cortex fasteners are compatible with TimberTech AZEK, PRO, and EDGE full-profile boards only. Within TimberTech AZEK: Cortex is available in all 6 Vintage Collection® colors as well as Slate Gray and Brownstone from the Harvest Collection. Approved for use on deck stairs. Approved for use in MAX (1.5”-thick) boards.

TOPLoc Fasteners
TOPLoc screws are compatible with grooved, scalloped, and full-profile boards from TimberTech AZEK, PRO, and EDGE lines.
They are also approved for use in MAX (1.5”-thick) boards.
3.) Appearance

Cortex Screws
Cortex screws drive to just below the deck surface and are then capped with collated plugs made from the same deck material as the deck board (hiding the screw head).

TOPLoc Fasteners
TOPLoc screws feature screw heads that are color-matched to the hue of your deck boards. They install flush with, or just below, the deck surface.
Where Can I Get Inspiration & Guidance for Projects With Cortex Screws?
Feeling ready to get started on your decking project? Dive into the Deck Building Resource Center and get the 411 on installing TimberTech AZEK with Cortex.
Or, if you’ve decided TOPLoc color-matched fasteners are more you’re style, learn How to Install TimberTech AZEK Decking With TOPLoc Color-Matched Screws.
Still have questions? Or just feel most comfortable with an applications and materials expert on-hand? Partner with a TimberTech-registered contractor to be sure you get the job done right.