Monorub is a single component, polymer modified cementitious mortar for the filling of blow-holes and small surface defects in pre-cast and in situ concrete, whilst providing an aesthetic yet durable finish. The incorporation of a polymer enhances adhesion and imparts a high degree of water repellency to the surface of concrete, making it denser and more impermeable. Once cured, it can be readily overcoated with specialist membranes in the Flexcrete range to provide further protection and aesthetic quality.