A construction board comprising of a foam body, said foam body having first and second planar sides; and a facer affixed to said first or second planar surface, said facer including a cellulosic substrate and a water-resistant coating layer, said cellulosic layer having first and second planar sides, where said first planar side of said cellulosic substrate is affixed to said foam body and said second planar side carries said coating, where said cellulosic substrate is substantially devoid of fiberglass, where said water-resistant coating layer has a thickness of less than 1.5 mm, and where said water-resistant coating layer includes a polymeric binder and a filler dispersed throughout the binder.