Patent ID: 7754320

Claim:
A composite building article having a first zone comprises a fiber cement substrate having a porosity of between about 20%-40% by volume which comprises predominantly fiber cement comprising about 20-60 weight % cement; about 0 to 60 weight % silica; about 0.1 to 15 weight % cellulose fiber; and about 0-5 weight % of at least one additive; a second zone which comprises predominantly an EB curable urethane acrylate resin having a solids content of at least 80%, and a subsurface interfacial zone interposed therebetween, the subsurface interfacial zone comprising an interlocking matrix formed of the EB curable urethane acrylate resin and the fiber cement, wherein said interfacial zone is integrally formed with the first and second zones and configured to increase durability of the building article.