How To Cut Composite Decking

Composite decking is an advancement made in the lumber industry back in the 1980s. The alternative to traditional wood decking is made of plastic and wood shavings, which are formed into dimensional boards by either compression molding or co-extrusion. These boards are largely used for decking today despite their higher price due to the savings from reduced maintenance costs. Usually, homeowners can expect nothing more than sweeping and washing occasionally to keep their composite decking looking good as new. If you are a home DIY’er who is thinking about putting in a composite deck, you should be prepared with a plan to get the job done right. In order to put in your deck, you will need to know exactly how to work with composite decking so that the final installation looks clean and professional.

Tooling Requirements

Cutting composite decking is quite similar to cutting regular lumber. You can use a couple different saws including a circular saw, miter saw, or a table saw. The round blade is key to getting straight clean cuts that do not warp the board from excessive heat. A coarse, carbide-tipped blade is recommended to make quick cuts that do not build up a lot of frictional heat. If using a 7 ½” circular saw, use a blade with around 20 teeth. If using a 10” table saw or 12” miter saw blade, choose a blade with around 40 teeth. In addition to cutting tools, you will also need a speed square, non-staining chalk line, and tape measure to move the project along smoothly. These tooling recommendations will give you the best results for your deck.

Board Preparation

Be sure your boards are fully prepared so that the cutting process is headache-free. Ensure your boards are covered and stored in a cool, dry place so that they are not dirty. Before cutting, it is a good idea to wipe the boards clean to guarantee the boards are perfect. Once the boards are clean, you will need to prepare the outer edges so that they are guaranteed square. To do this, use a speed square to measure a line across the short length of the board approximately ⅛” from the edge. Cut along the line to remove the small outer piece. You will now have a perfectly square board. For composite decking, you do not need to do any surface sanding. In fact, this can often void warranty on your product. Composite boards are specially designed with a polyethylene shell that protects them from fading and wear. Sanding can actually decrease the performance, too, so be sure not to do any sanding. After this step, you are ready to begin cutting lengths for installation.

Straight Cut Boards

Your prepared boards are easily cut using any of the above mentioned saw options. Most decks will be made using straight boards on a rectangle design. For this, straight cuts will be sufficient to complete the deck. Use your speed square and chalk line to ensure you have your cut lined up perfectly. When measuring for cuts, it is common practice to measure boards a few inches longer than needed and allow them to overhang on one edge. Then, a single straight cut is made through the excess to yield a perfectly flush edge on the deck. This will give your deck an incredibly professional appearance.

Angle Cut Boards

If your deck has diagonal sections, or you are running boards at an angle from a flat edge, you can make special mitre cuts to fill the deck in. A mitre saw can precisely make angle cuts for all of your boards. Unless you have special jigs, any other saw will be unsatisfactory for delivering consistent angles to your deck boards.

Curved Boards

One special feature of composite lumber is that the composition allows for easier shaping. These partially plastic boards will bend when heated, allowing workers to create complex curves and bends in the wood. This can yield a truly unique appearance if done correctly. For most home DIY’ers, getting a professional contractor involved is the best route as bending is difficult even with the right heating equipment. Nonetheless, the cutting process is just as easy as with straight or angled boards. Keep in mind that you may need small additional cuts near edges due to the eccentric shape of the curves.

Cutting composite decking is simple and accessible for any home DIY’er. Most of the required tooling is already needed for regular wood, so chances are the average woodworker is already equipped to handle composite. The only thing left to do is decide what color you want your new composite deck to be.