The invention relates to the provision of apertures in building board materials, such as in ceiling or walls. A first aspect relates to an aperture edging member for forming a substantially smooth or "flush" aperture within a surface member. The edging member includes a substantially planar rim portion adapted to be attached to the surface member, a lip provided along one edge of the rim, and a flange depending from the lip in a substantially transverse direction to the rim so as to fit within the aperture. The second aspect relates to an aperture edging device which has an intermediate section with a pair of arms depending transversely therefrom to form a substantially c-shaped configuration to envelope the edge portion of the surface member. An advantage is that a strong rigid vertical face is created in the plaster board, minimizing the possibility of damage thereto. Light fittings, or other fittings may be associated with the device.