Wherever damp is present, it is good practice to eliminate the damp from its source, as well as treat the affected surface. Flash Harry produces a full range of Damp Doctor Products, for optimum treatment of all your damp problems. An interior and exterior priming coat, for the treatment of rising and penetrating damp. Damp Sealer binds the surface, leaving a smooth finish and promotes excellent adhesion of decorative coatings. Damp Doctor Damp Sealer is a water based priming coat, for the treatment of rising and penetrating damp. For use on Vertical walls, where superficial damp has caused discoloration and peeling paint. Damp Sealer binds the surface, leaving a smooth finish and promotes excellent adhesion of decorative coatings. Damp Doctor Damp Sealer will provide a smoother finish than Damp Doctor First Aid Coating and is therefore more commonly used on interior applications