Abstract: There is provided a facing sheet for cement boards comprising a scrim and polymer film. The scrim has a plurality of intersecting yarns defining an open mesh pattern with an inner face defining a grid profile for mechanical interaction with the cementitious composition of the cement board. The polymer film is joined to an outer face of the scrim and defines a repeating pattern of openings. The polymer film facilitates the mechanical interaction between the grid profile of the scrim and the cementitious composition and allows the passage of moisture from the cementitious composition during hardening of the cement board. The scrim may include glass fibers yarns and the polymer film may be formed by a gravure rolling process. A cement board may include a second facing sheet on a surface opposite the first facing sheet.