Solid vs Grooved Composite Decking: Differences & Fasteners

December 2, 2021

While the image in your mind of a standard deck board is likely that of a smooth-edged rectangular board, composite decking comes in a few different profiles. In addition to the solid-edge board you’re familiar with — called a “square-shoulder” board — you also have the choice of grooved boards. Grooved composite decking is one type of deck board that features grooves along both sides of the board, ideal for hidden clip fastening systems.

So why is it important to think about different composite deck board shapes?

✓ Because the type of deck board you choose will affect your installation and final deck appearance, as different fasteners are designed to work with specific deck board shapes.

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Follow these steps to determine whether square-shoulder (solid edge) or grooved composite deck boards are right for your project.

Step 1: Learn About Composite Deck Board Shoulder Types

Board shoulder type refers to how the sides of the board look.

TimberTech^® capped polymer and capped composite deck boards feature two board shoulder types:

Board Shoulder Types

Grooved

A board with capped grooves along both sides to allow for hidden fastening.

Square-Shoulder

A solid-edge board that allows for easy top-down installation. Square-shoulder is sometimes referred to as a “solid” board.

How Do You Groove Composite Decking?

Easy — you don’t. All TimberTech decking lines and collections feature a grooved board option, so you don’t have to groove your own boards.

TimberTech Grooved Composite Decking

Our encapsulated grooved boards feature protective capping that runs through the grooves for maximum protection.

If you find yourself in a situation where you need to groove a TimberTech square-shoulder board, you can add a groove. Be sure to follow the installation guidelines for your chosen deck boards.

Now that you know your composite deck board shoulder options and that TimberTech offers superior grooved composite decking, you can next ask:

• What are my fastener options?
• Which fasteners are compatible with each board shoulder type?
• Which board type and fastener pairing gives me the installation and final appearance I’m looking for?

Step 2: Discover Your Composite Decking Fastener Options

The type of deck board and the TimberTech decking line you choose affect which fasteners you can use.

Why? Because certain fasteners are designed specifically for grooved composite deck boards while others are designed for square-shoulder boards.

Step 3a: Discover Hidden Clip Fasteners for Grooved Composite Deck Boards

Thinking about grooved composite deck boards for your build? Explore these compatible hidden clip fasteners to decide which is best for your project.

*Refers to TimberTech capped polymer and capped composite decking lines.

Interested in top-down fasteners for grooved boards?

While certain top-down fasteners can be used with grooved composite deck boards, remember that the main reason to choose grooved boards is for their compatibility with hidden clip fasteners.

However, you may use a combination of top-down fasteners and hidden clip fasteners for your project. For instance, top-down fasteners will need to be used to secure the boards closest to your home.

Step 3b: Discover Top-Down Fasteners for Square-Shoulder Composite Deck Boards

Square-shoulder boards are compatible with both visible and hidden top-down fasteners to suit your preferences and project needs. Note: For TimberTech AZEK square-shoulder boards, we recommend top-down fasteners.

Step 4: Consider Grooved vs Solid Composite Decking

Now it’s time to take what you’ve learned and determine whether grooved or square-shoulder (solid-edge) composite decking is right for your project.

Deciding which deck board shoulder type is best for your project will depend on how you value these factors:

• Installation ease
• Final deck appearance

Installation Ease: Grooved vs Square-Shoulder

Each board type and fastener pairing requires different installation methods, but easy, straightforward options are available for both board shoulder types. You’ll also need to make sure you have access to the appropriate tools for your chosen fastening method — either by buying them or renting them.

Final Deck Appearance: Grooved vs Square-Shoulder

The board shoulder type you pick affects your final deck appearance by influencing your fastener selection.

Think about whether you’d prefer a fastener-free surface to one that features visible screw heads or plugs — remember, the primary reason for choosing grooved composite decking is so you can use hidden clip fasteners.

Get the Look You Want With Grooved or Square-Shoulder Boards

Finish Your Edges With Square-Shoulder Boards

You’ll also want to think about your deck perimeter — will board edges be visible? Even if you choose grooved boards for your deck surface, use square-shoulder boards for your stairs and perimeter for a nice clean edge.

Solid vs Grooved Composite Decking: See Your Options Up Close

Now that you know the differences between composite deck board shoulder types, you’re ready to start exploring your deck board color options. Order free samples of your favorite TimberTech decking colors to see our nature-inspired decking up close.

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