Ecological confinement option

Claim 1

A fence system comprising: at least one vertical treated wooden post; at least two C-shaped galvanized steel expansion stringers, each of said stringers comprising a central portion with upper and lower flanges extending therefrom, said each stringer having an end portion with a plurality of vertically oriented elongated slots thereon, each of said end portions being defined by said central portion of the respective stringer with said upper and lower flanges removed therefrom, said each end portion having a first face and a second face opposite the first face wherein the first face abuts a surface of the post, said end portions of the respective stringers being disposed adjacent to each other and being secured to said surface of said post by screws having tapered heads, said screws extending into said post through said slots of the respective end portion and forming a small clearance between each of said screw heads and said second face of the respective end portion; and a plurality of treated high density polyethylene plastic pickets, each of said pickets having a surface for abutting and attaching to the central portions of said at least two expansion stringers, at least one of said pickets having said surface with an undercut formed thereon, said undercut of said at least one picket overlaying said slots of one of said end portions and providing clearance for the heads of the respective screws extending through said slots of said one end portion, wherein said vertically oriented elongated slots, said small clearance between the screw heads and the second faces of the respective end portions, and said undercut of said at least one picket are provided to accommodate vertical thermal expansion of said plastic pickets attached to said expansion stringers.