DIY Composite Deck: What to Know Before You Build

August 17, 2021
HomeOutdoor Living IdeasDIY Composite Deck: What to Know Before You Build

Considering upgrading your backyard with a new composite deck — and wondering if you can DIY the build? (Spoiler: you likely can). Or, are you thinking of resurfacing your existing deck with low-maintenance decking? Before you begin, make sure you’ve asked yourself the right questions — and considered the variables that will influence your build — so you know if a DIY project is right for you.  

Benefits of DIY-ing Your Composite Deck 


Saves you on labor costs

Gives you complete control of your deck build

Can be a challenging but fulfilling project

ALREADY KNOW YOU WILL DIY? 
Jump into our Deck Building Resource Center for step-by-step tips and best practices, as well as guided install videos. EXPLORE 

Step 1: Determine if You’re Ready to Build Your Own Deck

Determine if you're ready for a DIY composite deck build

The first step in your DIY composite deck journey is deciding if you’re ready for it. The deck building process will vary depending on whether you’re building a brand new structure, resurfacing an existing substructure, or extending your deck.  

Questions to Ask Yourself Before Deciding to DIY Your Deck 


Step 2: Choose the Right DIY Decking Materials

As far as the highest-performance DIY decking materials go, you have two primary options:  

DIY composite deck materials include capped polymer decking

Capped Polymer Decking 

Our premium decking option, made of fully engineered material with no wood, TimberTech AZEK® capped polymer decking offers:  

DIY composite deck materials include capped composite decking

Capped Composite Decking 

A superior option made of organic and engineered material, TimberTech PRO® and TimberTech EDGE® capped composite decking deliver:  

Each of our decking lines boast superior performance vs traditional wood — with some differences across product lines.   

Multiple Options, No Compromises 

Explore our 3 unique decking lines to find the right fit for your (life)style.  

Step 3: Design Your Composite Deck 

When designing your DIY composite deck, there are several factors — and options for an easier build — that you’ll want to consider:  

DIY composite deck height and shape considerations

Deck Height & Shape 

Your deck height and shape will impact the time and effort involved in your DIY project. 

For an easier build: Stick to a low- to mid-level deck to avoid installing stairs or a railing which increase the complexity of your build. Choose a simple shape such as a square or rectangle — classic, but far from boring.  

DIY composite deck board pattern considerations

Deck Board Pattern 

Blocking should be installed edge to edge to allow for fastening of the interior blocking.

For an easier build: Go with straight-laid deck boards. All patterns other than straight boards will require additional substructure framing and extra cuts and calculations, all of which increase build complexity.  

DIY composite deck end-cut covering options

Covering End-Cuts 

Use exterior-grade fasteners to fasten through the outside of the joist.

For an easier build: Cover the ends with a fascia board raised to be flush with the deck.

For the most polished look — without too much extra effort — choose a picture frame border to finish your ends.

While deck board colors won’t affect your installation, they do affect the overall look and feel of your deck. 

Deck board color swatches without labels

Find the Right Color for You

From deeply saturated hues to light and bright tans, we have just the right color for your space.

Start Designing Your Decking Masterpiece 

Play with deck shape, height, and color in our 3D Deck Design tool.  

Step 4: Get Familiar With Best Practices for Installing Composite Decking 

TimberTech composite decking installation shares many of the same best practices as traditional wood installation — with some minor differences. Make sure you’re familiar and comfortable with some of the processes you’ll be undertaking in a DIY deck build before you commit to the project. 

DIY composite deck substructure framing best practices

Substructure Framing 

Standard deck joist spacing is 16” on center, or 12” for a more rigid feel — same as many traditional wood options. Blocking should be spaced every 4’ to 6’ in between joists, and joists should always be level and in-plane with one another and across the tops.   

Get a firsthand look at substructure framing by watching the video.  

DIY composite deck board spacing best practices

Deck Board Spacing 

Deck board spacing refers to the gaps between the sides and the ends of the boards. Proper spacing varies between wood and composite decking because the two materials expand and contract in different directions. Accurate deck board spacing will be crucial when DIYing your deck. 

Fastener & Deck Board Pairings 

Choose between top-down fasteners (like those used with traditional wood) or hidden clip fasteners. Keep in mind that certain fasteners only work with particular decking lines and board profiles.  

For easy pairings, go with one of these combinations — and check out our instruction video for each to see the installation process and decide which is right for your DIY composite deck project.    

Cortex hidden fastener application with plastic-tipped hammer

TimberTech AZEK With Cortex® 
Hidden Fasteners 

  • Top-down fasteners 
  • Screws hidden by plugs made of TimberTech deck boards 
  • No pre-drilling required 
TOPLoc top-down fastener application with a drill

TimberTech AZEK With TOPLoc® Color-Matched Screws 

  • Top-down fasteners 
  • Color-matched screws blend in with deck surface  
  • No pre-drilling required 
CONCEALoc hidden clip fastener application with a drill

TimberTech PRO & EDGE With CONCEALoc® Hidden Fasteners 

  • Hidden clip fasteners between grooved boards 
  • Fastener-free surface 
  • Pneumatic install option 

DISCOVER THE EASIEST WAY TO BUILD A DECK 
With TimberTech AZEK capped polymer decking, top-down fasteners, and a panelized railing system. LEARN MORE 

Step 5: Consider Your Railing Options 

DIY composite deck railing options and considerations

No DIY composite deck project would be complete without railing. Just like your composite decking options, TimberTech railing materials are designed with premium aesthetics and exceptional durability — which means minimal maintenance work for you.  

Does My Deck Have Code-Related Railing Requirements? 

If your deck is below 30” off the ground, it likely will not require a railing. If it’s higher than 30” at any point in the design, then that section will require a railing for residential code compliance and safety. Always check with your local building codes for railing requirements.  

Regardless of code requirements, you still may opt to choose a railing as a design element or for practical reasons like keeping guests from stepping off into your deck’s beautifully landscaped perimeter.  

DIY Considerations for Your Railing 

The TimberTech railing portfolio offers numerous railing profiles as well as customization options to create a deck perimeter that’s all your own.  

But when it comes to DIY-ing deck railing, one of the most important considerations to think through is the difficulty level of railing installation. For a straightforward, easy railing installation, it’s best to go with a panelized railing system.  

Easiest railing installation with Impression Rail Express

Choose the Easiest Railing Installation 

Looking for a straightforward install that gives you a sleek, modern railing? Go with Impression Rail Express®. This panelized railing features pre-assembled balusters so you can install the railing as one piece, rather than installing each individual baluster.  

And yes — they work with stair angles, too.  

Prefer to Customize Your Railing?  

Discover all your railing options and mix and match materials for a truly curated deck perimeter.  

Step 6: Think Through Deck Lighting 

Once you have the bigger pieces like deck design and material figured out, you can start thinking about some of the details. Note that permanent deck lighting will likely need to be installed before you lay your deck surface. Always closely consult appropriate install guides, and make sure you are comfortable with, and knowledgeable of, electric wiring best practices. 

Increase ambiance and safety with deck lights

Increase Ambiance & Safety With Deck Lights 

Enjoy your deck after dark with deck lights. Deck lighting adds ambiance and improves safety through increased visibility.  

Lighting options include temporary lights like string lights and permanent lighting for your deck surface and railing.  

In-deck lighting may require a contractor to install.  

PREFER TO WORK WITH A PRO? 
Partner with a TimberTech-registered contractor who can ensure your deck is designed and built just the way you want it — and to code.  FIND A CONTRACTOR 

Step 7: Start Your DIY Composite Deck Project With Samples 

With the guidance you need for your DIY composite deck project, you’re ready to begin planning for your build. Get your creative juices flowing by ordering up to four free composite decking samples of your favorite colors. Be sure to place them all in the area your deck will be built to see how they look in different lighting throughout the day.  

See & Feel the TimberTech Advantage

Our capped polymer and capped composite decking lines combine recycled material with all the beauty of traditional wood.

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