- 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](https://homesteady.com/facts-5831292-composite-decking-.html) for the stair treads will be screwed to the top of each step on the stringer.
- Place the composite decking boards on a work surface. Mark the measurement from Step 1 onto one of the boards with a pencil.
- 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.
- 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.
Things You Will Need
- Tape measure
- Composite decking
- Miter saw
- Use composite decking screws to secure the decking boards to the stringers. A composite decking screw has a small screw head that can help countersink the screw to the correct depth in the board.