How to Cut Composite for Stairs

Composite is a synthetic decking material that is made from a combination of plastic and wood. It is made to appear like natural wood and comes in a wide selection of colors. Composite decking is durable and low maintenance. Unlike regular wood decking, you will not have to refinish it every few years to keep it looking new. Cutting composite for deck stairs can be done with a carbide-tipped saw blade in a basic miter saw. Careful measurements and cutting will result in an attractive composite set of stairs for your deck.

  1. Measure the width of the stairs from the outside edges of the stringers with a tape measure. The stringers are the framework for the stairs. The composite decking for the stair treads will be screwed to the top of each step on the stringer.

  2. Place the composite decking boards on a work surface. Mark the measurement from Step 1 onto one of the boards with a pencil.

  3. Position the marked board flat on the table of the miter saw. Slide the board along the table until the outside edge of the pencil mark lines up with the saw blade. Pull the trigger and guide the saw down through the board. Lift the saw back up through the wood to the start position and release the trigger to make the cut.

  4. Measure and mark each board to length, as you cut them, until you have cut enough boards for each step on the stair stringers. Depending on the size of the composite decking and stringer size, you may need two to three decking boards per step.


  • Wear eye and ear protection when operating a miter saw.
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