Is the Patriot Steel Post Mount able to be screwed onto composite decking?

The Patriot Post Mount can be installed into wood, concrete or composite surfaces. That said, we do not suggest securing the Patriot to deck boards alone. We recommend using blocking attached to the deck framework, so the post is being secured to something more structurally sound than just the deck board.

We also do have the SPB Kit/Underdeck Anchoring Plate available for added stability. You can find that here.