This paper, and the research it describes, examines the benefits and importance of good site practice for the aftercare of lime mortars and renders. The control of moisture is explored in relation to mortar development. This work shows the way in which proper aftercare in terms of wetting, drying and protection enables lime mortars and renders to perform at their best. It is important that Architects, Engineers and specifiers can rely on craftspeople who understand the need for aftercare and ensure that best practice is followed. This paper provides a scientific explanation of how the traditional practice to control moisture, before and immediately following the application of building limes, works to improve set and durability. Scientific reasons for the traditional site practice of damping down the background to application of lime mixes, and the subsequent tending of finished work, are explained by reference to laboratory research developed for the purpose.