How do the fasteners work on stairs? Is it still hidden?

Hello, and thank you for your interest in Trex. There are 2 methods of installation for stair applications: 1) Trex recommends using a square edge deck board as the front and back stair treads and face screwing both boards with a Trex recommended composite decking screw. 2) As a second option you can use a grooved edge deck board as the back stair tread, and a square edge deck board as the front stair tread. To fasten these boards first you will need to route one side of the square edge deck board with the Trex Router Bit to allow for the use of the Trex Hidden Fastener between the stair treads. Then you will secure the back stair tread with Trex starter clips, use the Trex Hidden Fastener between the treads and then finish the installation by face screwing the front edge board with a Trex recommended composite decking screw. I hope this helps! Thanks, Tori - Trex Customer Care Team