How tall can a Trex privacy fence be?

Trex privacy fencing is designed to be built as tall as 12 feet high. Fences up to 8 feet tall do not require mid-rails. Fences above 8 feet tall are created by stacking panel kits (one mid-rail for 9-10 ft. tall and two mid-rails for 11-12 ft. tall). You can view shop drawings for Seclusions, with vertical pickets, and Horizons, with horizontal pickets, illustrating placement of brackets, dimensions, and materials needed for the various heights.