Described herein is a multi-phase polymer binder including an aqueous polymer dispersion, an optional hydrophobic emulsion, and an optional surfactant. The polymer binder, when dried, provides a water uptake of less than about 5 g/m2/20 min, a seal strength of at least about 200 Newton/meter (N/m) as measured at 25° C. or at 90° C., and sufficient block resistance to impart no substrate damage.