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Cortex Screws: What They Are & When to Choose Them

July 25, 2022
TimberTech AZEK Cortex screws in multi-colored deck

If you’re planning to build a composite deck, you’ve likely come across cortex screws in your research — along with many other options like hidden clips and color-matched fasteners. So, you’re probably wondering, what are cortex screws, and are they the right fastener for my deck project? To help you in your journey, we’ve got the answers to your questions, as well as additional guidance to cover all your bases.

How Fasteners Affect Your Deck Project

When building a deck, you’ll use fasteners to securely attach deck boards to the deck substructure (the frame that consists of posts, beams, blocking, and joists). But with multiple fastener options available, how do you know which is best for your project?

Knowing which deck fastener to use for your project will depend on:

With this information in mind, you can decide whether Cortex® is the right type of fastener for your project.

What Are Cortex Screws?

Cortex screws are hidden, top-down fasteners with material-matched plugs that secure your deck boards to the joists below. The plugs are made of the same material as your composite deck boards for a satisfactory match — giving you the appearance of a fastener-free deck surface.    

Coastal style gray composite deck with AZEK cortex screws for a fastener-free surface

Cortex Screws

Include plugs made from the same material as the deck boards for a seamless final look.

Feature a special driving tip that automatically installs the screw at the correct depth.

Feature a high-quality, ACQ-approved, specialty deck screw with a TORX® ttap® drive system.

Cortex Fastening Systems From TimberTech

Within the TimberTech® fastener portfolio, you have two cortex options, TimberTech AZEK Cortex screws for our polymer decking line and Cortex for PRO & EDGE composite decking.

AZEK cortex screws for French White Oak decking product image

Cortex for Capped Polymer Decking

A secure, hidden fastening system with collated, material-matched plugs, designed for TimberTech capped polymer decking. TimberTech AZEK Cortex screws are the top-recommended fastener for TimberTech capped polymer decks with no pre-drilling installation required.

Cortex screws for Tigerwood decking product image

Cortex for Capped Composite Decking

A secure, hidden fastening system with material-matched plugs, designed for TimberTech PRO® and TimberTech EDGE® decking. However, you must pre-drill with the proper bit for installation.

When to Choose Cortex Screws for Your Project

When planning for your composite deck build, you should know that cortex fasteners are only compatible with certain board profiles.

AZEK Cortex screws are compatible with full-profile deck boards

Cortex Screws Pair With:

Full-profile TimberTech deck boards. Full-profile boards are those that have a standard flat bottom design.

Why Choose Cortex Instead of Other Fasteners?

TimberTech cortex screws offer several benefits that make them an ideal choice for many projects and applications.

Easy top-down fastening installation

The strongest hidden fastener option offered by TimberTech

Can be used for boards on stairs and the perimeter (while not all hidden fasteners can)

Provides a polished final look with material-matched plugs that hide screw heads.

And when you choose our capped polymer decking, there are even more benefits to using TimberTech AZEK Cortex screws.

Benefits to Using Cortex With TimberTech AZEK

No pre-drilling required to install TimberTech AZEK Cortex screws

Faster installation with TimberTech AZEK Cortex screws, which feature collated plugs with a pre-aligned grain pattern

Hidden Cortex Fasteners vs TOPLoc® Color-Matched Fasteners

Because of their similarities — primarily their top-down installation — cortex fasteners are often considered alongside our TOPLoc fastening systems. While cortex is a top-recommended fastener for TimberTech deck boards, you may find that TOPLoc fasteners better fit your needs and preferences.

Both screws feature top-down installation, but they differ in fastener type, which boards they’re compatible with, and their final deck surface appearance.

1.)  Fastener Type

AZEK Cortex screws featuring collated plugs

Cortex Fasteners

Hidden fasteners that are covered by plugs made from the same material as your chosen deck boards. 
TOPLoc color-matched fasteners product image with brown screws

TOPLoc Fasteners

Visible screws that feature heads color-matched to your deck surface.

2.)  Compatibility

Close up of Dark Hickory decking installed with AZEK Cortex screws

Cortex Fasteners

Compatible with all TimberTech full-profile boards. They are the only hidden fastener that can also be used for boards along stairs and the perimeter of your deck.  
Close up of Silver Maple decking installed with TOPLoc color-matched screws

TOPLoc Fasteners

Compatible with grooved, scalloped, and full-profile TimberTech deck boards.

3.)  Final Deck Appearance

Scandi-inspired deck with Weathered Teak decking installed with AZEK Cortex Screws

Cortex Fasteners

The material-matched plugs align with the deck board grain for a polished, fastener-free aesthetic.
Close-up of composite deck stairs with TOPLoc color-matched screws

TOPLoc Fasteners

TOPLoc fasteners install flush with the deck board surface and feature screw heads color-matched to your deck board color for a subtle, blended-in look.

Inspiration & Guidance for Projects Using Cortex Screws

Now that you’re more familiar with cortex screws, you’re ready to get more insight for a successful deck building project. Explore the Deck Building Resource Center for more information — including helpful guides and videos — on installing TimberTech decking. Plus, you can get deck design advice, tips for choosing your railing, decorating ideas, and more.

See Cortex Installation With TimberTech Decking

The best-of-the-best decking, no matter which line you choose. Because where you live should never be where you settle.

A deck made with French White Oak decking on a brick-clad home

Have questions? Talk to one of our TimberTech experts for answers. Prefer to have help with your build? Connect with a registered contractor in your area to take the stress out of your DIY deck build.

Bring the Beauty of TimberTech to Your Backyard

Work with a TimberTech pro for a build that transforms your outdoor living space.

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