A wet-formed permeable mat composed of wet use chopped strands (WUCS), chopped roving, and potentially unidirectional roving coupled with an alkaline resistant binder are combined to create an randomly oriented open mat structure with a high degree of openness that can be used in cement backerboard applications. The cement backerboard that is subsequently formed from the wet-formed permeable mat has lower binder content, superior decorative finish, and better permeability control than known glass scrim systems and can be produced in a single continuous step.