Can you screw this material down or is this not recommended.

Hello, and thank you for your interest in Trex. The grooved deck boards are designed for use with Trex hidden fasteners, however yes they can also be screwed down if needed. We also offer a square edge deck board in every color for face screwing as well. For aesthetic and warranty reasons please select a composite deck screw from our Trex recommended fastener list. Thanks, Tori - Trex Customer Care Team