Precast concrete balcony units are generally cast in their in-situ orientation to ensure the best (architectural) finish to the visible underside and edges. The top face is trowelled smooth, often to falls which allow water run of to preformed / integrated gutters and outlets. This trowelled top face can additionally have an acid-etched, grit-blasted or retarded finish. Alternatively it can be left un-treated for a site applied finish or covering.