RIW Cementflex is a two component, cement based, polymer rich and flexible waterproof coating with excellent adhesion to prepared concrete and masonry substrates. When mixed, it exhibits a good degree of thixotropy to enable ease of application by brush or spray techniques to give an even finish with no sagging even in vertical situations. It hydrates to form a durable, highly alkaline, permanently elastomeric coating which not only protects the concrete, or other substrates, from water penetration and carbon dioxide diffusion, but also accommodates movement in cracks. The elastomeric flexible waterproof coating maintains its flexibility under permanent immersion and when exposed externally.