an elongated structural article , having a continuous profile extrusion with spaced apart layers defining a portion of a cavity filed filled with thermoplastic pre - expanded beads expanded with steam in - situ causing the beads to securely bond together and to the profile extrusion . the article is cut to a length forming ends having an exposed foam core . a system for manufacturing the article is also disclosed having a profile extrusion die for forming an axially profile defining a wall surrounding a cavity , a tubular shaping mold located axially downstream of the extrusion die sized to support a length of the profile as it passes there through . a bead dispenser is oriented to introducing pre - expanded beads into the profile cavity while within the shaping fixture and a steam tube is oriented downstream of the introduction of pre - expanded beads . control valves regulate the flow of pre - expanded beads and steam into the profile cavity .