Installation Basics 2.0 for Manufactured Decking (Butt Joints, Clean Cutting, etc.)

"There's nothing quite as satisfying as installing a beautifully lined up, level deck."

Jim Coshow


Every great outdoor living space starts with a good plan and a solid foundation—which is what our decking series is all about. In this series, we sit down with our good friend Kevin Kunka of Trex Company to cover some of the ins and outs of executing a successful decking project. Trex is the world’s largest manufacturer of wood-alternative decking products and a veteran in the outdoor living industry.

In today’s video, we cover some less common but critical installation best practices that will help you achieve consistency and precision on your installs. Kevin shares helpful tips on butt joints, clean-cutting, and picture-framing with manufactured decking.

Watch the video above or read a recap of our conversation below.

Butt joint best practices

It’s best to avoid butt joints if you can—but in some cases, there's just no way around them. If you find yourself in a situation where you have to install a butt joint, there are a few best practices that are critical for project success.

First, make sure your joists are completely level before installing any boards. Any discrepancies between joists will cause your manufactured deck boards to take on an uneven “wave” once installed. You may have to shave or shim your joists, but it’s worth the extra work upfront—uneven installs are almost always due to uneven joists below, and fixing them after the fact can be very challenging.

Second, add a nailer board or secondary joist where your two board ends will meet. With manufactured decking, fasteners need to be one inch from the side and one inch from the end of the board, and installed 100 percent perpendicular to the deck board—if you do that correctly on a single joist, your fasteners totally miss the single joist. If your design includes butt joints, you may want to install double joists as necessary to ensure each board will have a solid place to fasten into. Whether you go that route or simply add a nailer board where applicable, be sure to do this before installing the decking boards, as it’s very difficult to do after.

When fastening butt joints using hidden fasteners, use a separate clip for each board. If you try to “share” a clip between two boards, the boards may pop off the single clip due to normal movement with temperature changes.

Clean cutting

You always want to recut your boards before installing, even if you have a design that fits the length of your boards perfectly. Cutting your ends will ensure all of your boards are the right length and have smooth squared ends. Once you cut, the ends will seal up on their own, so there’s no need to apply end treatment.

If picture-framing is part of your design, here’s a trick to make cutting easier and more precise: Rather than measuring and pre-cutting your boards on both ends—which is tedious and leaves room for human error—install them before your picture framing and transition board, letting both ends “run long." Then, calculate where you will need to cut your deck boards to properly interface with your transition board(s) and your picture-framing. Once you have that figured out, snap a chalk line using purple chalk (other colors won’t remove easily). Now all you have to do is run a circular saw along your line and you’ve got a clean-cut, straight edge to work with.

We hope these tips and best practices help make your next decking project run smoother. For more helpful tips and trusted advice, check out our guide to choosing a decking surface and part one of our installation basics conversation with Kevin.