Patent ID: 7045474

Claim:
A reinforcement for resisting flexure of a cementitious board having opposed faces, comprising: an open mesh of high modulus of elasticity strands, wherein the high modulus of elasticity strands comprise E-glass, and wherein the alkali resistant thermoplastic material comprises a core sliver of thermoplastic fibers commingled with the high modulus of elasticity strands, and a plurality of sheath thermoplastic fibers which cover the core sliver thermoplastic fibers and the high modulus of elastic strands; wherein the strands are covered by an alkali-resistant thermoplastic material adapting the open mesh for embedding in the cementitious board; the strands extending across one another to define a mesh thickness; wherein the open mesh is adapted with the mesh thickness for two embedded layers in the cementitious board; and wherein the open mesh is adapted with the mesh thickness for positioning each embedded layer about 1/32 inch to about 1/16 inch from a corresponding one of the opposed faces to avoid spalling, while each embedded layer is spaced from a neutral axis of flexure of the cementitious board to resist flexure of the cementitious board; wherein said alkali-resistant thermoplastic material is co-extruded with said strands to provide a substantially continuous coating of said alkali-resistant thermoplastic material about said strands; and wherein said alkali-resistant thermoplastic material is selected from the group consisting of polyolefins and olefin copolymers.