A sill drainage member for a window assembly which can include at least one sash. The sash includes a window pane in a frame which can be a single or double glazed window. The sill drainage member has an elongate body with an upper surface and lower surface. The upper surface includes drainage means which is adapted to drain moisture from a window sash. The sill drainage member is adapted to be located and fixed underneath a window sash. A method of installing the sill drainage member with slope blocks and double glazing units is also included and a method of retro fitting double glazed units in wooden sashes.