How to Install Trex Decking | Composites Installation

Trex composite decking is one of the most popular brands on the market today. While we get many questions about the brand, most revolve around Trex pricing and how to install their products. The good news is that the company has plenty of information online, including complete manuals.


With that in mind, our guide is geared to act as a quick reference during your decking project and is no substitute for official documentation. It will also let you know what to expect if you’re on the fence between doing the job yourself or bringing in a professional to tackle the job.

The Planning Stages

Before you charge batteries for your cordless tools or start prepping your frame you’ll want to take a minute and gather your tools. That’s assuming your frame is ready to go and up to code. If not, you’ll want to handle that first before rounding up the tools you’ll need for the job. 

Required Tools

  • Saws – Composite decking may be made from a mix of plastic and wood particles, but you can still saw through these boards or rip them like traditional lumber. That’s only if you have the right saw, however.
  • Circular Saws vs Miter Saws

    Circular saws and miter saws are the easiest options and can be rented if you don’t own one already. Trex has its own brand of saw blade as well with the Trex Blade, which is suitable for all of their material aside from Trex Elevations. 

  • Drills – A good powered saw will save you a lot of time on the job, and the same goes for cordless drills. It’s something millions of homeowners already have in their homes, and an affordable tool if you need to purchase one. Impact drivers can work as well, but you’ll need to be careful with the torque, or you could damage your deck boards. 
  • Drill

    Along with a standard 25’ tape measure, framing squares and speed squares are two other tools you’ll be thankful to have once your project begins. We also highly advise picking up a chalk line for rip cuts, but you only want to use one chalk brand with Trex. To keep those colored marks from becoming permanent, the company recommends using Irwin’s Straight Line Dust-Off Marking Chalk

    Potential Tools

    While you don’t necessarily need the following tools to complete your project, they are ones you’ll want to consider – especially for a large deck. Jigsaws will allow you to make detailed cuts, but an oscillating tool lets you get into some extremely tight spaces. Both are useful for posts and railings while a screw gun can speed up your work considerably. Safety glasses, gloves, and a dust mask should also be worn when installing Trex decking or any other type of composite decking. 

    Think Ahead…

    This is a good time to take a look at your deck frame and the joists. Are your joists completely level across the deck, or do you have a few stragglers that are a little higher or lower? Well, that could result in a wavy deck considering composite decking isn’t as rigid as wood. You can fix this with a line and a hand or powered planer.


    If you haven’t used butyl tape along the joists, now is the time to do that. This prevents moisture from accumulating and becoming trapped, which can cause pressure-treated wood to deteriorate well ahead of schedule. Make sure your joists are properly centered at 16” apart and consider any stair stringers or decking accents as well.


    It’s also a good idea to consider any end cuts ahead of time. Depending on the quality of the product and brand, the color may not go all the way through the deck board. With proper planning, you can keep those ends to a minimum, but picture framing your deck is also an option. Regardless, you still need to seal any cut ends with any type of composite deck board.


    When it comes to posts, you’ll want to make sure they are evenly spaced and set based on the code in your area. You can typically go 6 feet between each post, but it’s better to check beforehand. Always use the proper bracing, anchors, and carriage bolts when screwing the post to a joist.

    Installing your Deck

    Trex has four different collections of deck boards, but the installation process generally stays the same. Their Escape lineup has a slightly different method, and we’re only covering deck boards in this piece, not fascia boards, lighting, or railing.


    After unboxing your material, you’ll want to mix up the boards and lay them out. This allows you to put together a pattern that’s pleasing to your eye and is important when dealing with variegated colors. The company also recommends clean cutting the ends of your deck boards before installing Trex decking. While this may seem like an unnecessary step, factory edges aren’t always clean and square. Clean cutting the edges of your deck boards before installation can have a significant impact on the appearance.


    For Trex grooved decking or similar composite systems, you’ll want to take your starter clips and screw them along the joist to start your first board. This allows you to slide and lock in your first board before turning to the universal clips. These will give your deck a seamless appearance and are just as easy to install.


    You need to use one clip on every joist, and as you screw into the joist, the clips will draw the boards together. Near the ends, you need to make sure the clip is as close as possible, but no more than 25mm from the end. For boards with ends that are split on a joist, use a clip for each side, and a small sister joist beneath if necessary. The video below shows just how quick installation of Trex can be with proper preparation. 

    While the process to install Trex decking is something most homeowners can tackle, it’s important to make sure everything is properly gapped for expansion and drainage. With grooved decking, you need a 3mm to 5mm gap at the end of every board and at least 6mm to 13mm between decking and a wall or structure. For a truly seamless look, you can use the Pro Plug system from Starborn, which provides color-matched PVC plugs with grain texture to match your deck.

    Conclusion

    With the right tools and a few friends or family members, you can add a new deck onto your home over a weekend. The process we described to install Trex decking will work with other composite brands that have hidden fastener systems as well, but you should always refer to the company’s installation manuals to avoid any potential pitfalls with your warranty down the line.

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