A textile sleeve and method of construction thereof is provided. The textile sleeve has a water-based, impervious coating for protecting elongate members contained within the sleeve. The sleeve has a flexible, tubular wall of tightly braided yarns with a coating applied thereto to render the wall impervious to fluid. The coating is a water-based coating applied as two distinct, first and second layers. The first, underlying layer includes a dielectric enhancing additive and a thickening agent to enhance the impermeability of the wall. The second, outer layer contains a similar formulation as the underlying first layer, however, it is free of the thickening agent.