Abstract: The resistant to biological degradation of composite wood products is improved by applying a suitable aqueous dispersion of zinc borate onto the fibers to uniformly distribute and to adhere the zinc borate to the strands of the wood composite, applying a suitable adhesive to the wood strands, forming a strand lay-up and consolidating a lay-up under heat and pressure to form a consolidated product with zinc borate uniformly distributed therethrough.

Abstract: A fiber-cement trim board is formed by a fiber-cement core layer faced with a pair of fiber-cement surface layers of substantially equal thickness in the core layer and have a cement-to-wood ratio by weight of between 2 and 3.5 and at least 70% of the wood strands have a length longer than 10 min. Each of the surface layers is formed of a fiber-cement mixture containing wood strands, at least 80% of which have a length of less than 4 mm and a cement-to-wood ratio by weight of between 2 and 3.5. The board is covered at least on the two main faces by a water barrier coating.