Abstract: This invention relates to a sill for a door frame, whether a door is hinged, sliding, or bi-fold or otherwise, comprising or including a stationary sill member, whether of unitary or composite construction, a movable sill member with a surface thereon to act as a threshold (hereafter ‘threshold surface’) for said sill, and at least one moving means, wherein said at least one moving means acts on said movable sill member, directly or indirectly to move said movable sill member between, a first position wherein said threshold surface is retracted at least in part toward or within said stationary sill member, and a second position wherein said threshold surface is extended from said stationary sill member, said at least one moving means energised by a controlling event. The invention also relates to a method of providing and installing a sill for a door frame.