Flow-applied screeds are described, looking at where and how they are used, the performance requirements, and how typical flow applied screeds are formulated. A screed is defined as a layer of well-compacted material applied in-situ to a structural base, or other substrate, finished to a designated level. One of its primary functions is to provide a flat, smooth, sound surface at the correct level to receive another flooring material such as carpet, vinyl, and tiles. This can be achieved using many different types of screed. However, in recent years, particularly in Europe, flow-applied screeds have largely replaced traditional screeding methods and materials. These are self levelling, self smoothing screeds that provide the important benefit of speed and ease of application. Many flow-applied screeds are formulated on calcium aluminate cement (CAC) based binders. The formulation of these products, however, is complex and these products will often contain greater than ten components in order to achieve the requisite properties. The function and requirements of floor screeds are discussed, the different components used to formulate flow-applied screeds are covered, and the performance properties affected are identified. 12 refs.