POLYMER-BASED COMPOSITE STRUCTURAL SHEATHING BOARD AND WALL AND/OR CEILING SYSTEM

A polymer-based composite structural sheathing board for use in the formation of a building wall and/or ceiling system by overlaying and being secured to a structural building wall and/or ceiling frame, comprising: (i) a polymer material foam insulation core layer (60,70); (ii) a first polymer material solid or foam reinforcement layer (72,62) having a higher density than the insulation core layer; (iii) the insulation core layer and the first reinforcement layer each having a length, a width, and a thickness; (iv) the insulation core layer and the first reinforcement layer each having a first major surface and a second major surface that are defined by the length and the width of the insulation core layer and the first reinforcement layer respectively; and (v) a reinforcement sheet (64,74) located between the insulation core layer and the first reinforcement layer.